1231640640 has 336 divisors, whose sum is σ = 4500018432. Its totient is φ = 320495616.

The previous prime is 1231640617. The next prime is 1231640677. The reversal of 1231640640 is 460461321.

1231640640 is a `hidden beast` number, since 1 + 2 + 3 + 16 + 4 + 0 + 640 = 666.

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

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 3654552 + ... + 3654888.

It is an arithmetic number, because the mean of its divisors is an integer number (13392912).

Almost surely, 2^1231640640 is an apocalyptic number.

1231640640 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 1231640640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2250009216).

1231640640 is an abundant number, since it is smaller than the sum of its proper divisors (3268377792).

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

1231640640 is an equidigital number, since it uses as much as digits as its factorization.

1231640640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416 (or 394 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 1231640640 is about 35094.7380671234. The cubic root of 1231640640 is about 1071.9174399921.

The spelling of 1231640640 in words is "one billion, two hundred thirty-one million, six hundred forty thousand, six hundred forty".