15661505560 has 32 divisors (see below), whose sum is σ = 35310200400. Its totient is φ = 6251835520.

The previous prime is 15661505557. The next prime is 15661505579. The reversal of 15661505560 is 6550516651.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 379075 + ... + 418354.

Almost surely, 2^15661505560 is an apocalyptic number.

15661505560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15661505560 is an abundant number, since it is smaller than the sum of its proper divisors (19648694840).

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

15661505560 is a wasteful number, since it uses less digits than its factorization.

15661505560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797931 (or 797927 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 40.

The spelling of 15661505560 in words is "fifteen billion, six hundred sixty-one million, five hundred five thousand, five hundred sixty".