1311661640 has 32 divisors (see below), whose sum is σ = 2978830080. Its totient is φ = 519759552.

The previous prime is 1311661621. The next prime is 1311661643. The reversal of 1311661640 is 461661131.

It is not an unprimeable number, because it can be changed into a prime (1311661643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148952 + ... + 157511.

It is an arithmetic number, because the mean of its divisors is an integer number (93088440).

Almost surely, 2^1311661640 is an apocalyptic number.

1311661640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1311661640 is an abundant number, since it is smaller than the sum of its proper divisors (1667168440).

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

1311661640 is a wasteful number, since it uses less digits than its factorization.

1311661640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306581 (or 306577 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 1311661640 is about 36216.8695499763. The cubic root of 1311661640 is about 1094.6466169915.

The spelling of 1311661640 in words is "one billion, three hundred eleven million, six hundred sixty-one thousand, six hundred forty".