15755616521 has 4 divisors (see below), whose sum is σ = 15774761472. Its totient is φ = 15736471572.

The previous prime is 15755616479. The next prime is 15755616523. The reversal of 15755616521 is 12561655751.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15755616521 - 2¹⁰ = 15755615497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15755616523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9571241 + ... + 9572886.

It is an arithmetic number, because the mean of its divisors is an integer number (3943690368).

Almost surely, 2^15755616521 is an apocalyptic number.

It is an amenable number.

15755616521 is a deficient number, since it is larger than the sum of its proper divisors (19144951).

15755616521 is an equidigital number, since it uses as much as digits as its factorization.

15755616521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19144950.

The product of its digits is 315000, while the sum is 44.

The spelling of 15755616521 in words is "fifteen billion, seven hundred fifty-five million, six hundred sixteen thousand, five hundred twenty-one".