1331216640 has 288 divisors, whose sum is σ = 5089069440. Its totient is φ = 327573504.

The previous prime is 1331216633. The next prime is 1331216647. The reversal of 1331216640 is 466121331.

1331216640 is a `hidden beast` number, since 1 + 3 + 3 + 1 + 2 + 16 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (1331216633) and next prime (1331216647).

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×1331216640² = 3544275485225779200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1331216647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 447799 + ... + 450761.

It is an arithmetic number, because the mean of its divisors is an integer number (17670380).

Almost surely, 2^1331216640 is an apocalyptic number.

1331216640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1331216640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2544534720).

1331216640 is an abundant number, since it is smaller than the sum of its proper divisors (3757852800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1331216640 is a wasteful number, since it uses less digits than its factorization.

1331216640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3006 (or 2986 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 1331216640 is about 36485.8416375448. The cubic root of 1331216640 is about 1100.0596772031.

Adding to 1331216640 its reverse (466121331), we get a palindrome (1797337971).

The spelling of 1331216640 in words is "one billion, three hundred thirty-one million, two hundred sixteen thousand, six hundred forty".