15561601557 has 16 divisors (see below), whose sum is σ = 21459294720. Its totient is φ = 10020441600.

The previous prime is 15561601553. The next prime is 15561601567. The reversal of 15561601557 is 75510616551.

It is not a de Polignac number, because 15561601557 - 2² = 15561601553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15561601553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112132 + ... + 209037.

It is an arithmetic number, because the mean of its divisors is an integer number (1341205920).

Almost surely, 2^15561601557 is an apocalyptic number.

It is an amenable number.

15561601557 is a deficient number, since it is larger than the sum of its proper divisors (5897693163).

15561601557 is a wasteful number, since it uses less digits than its factorization.

15561601557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321724.

The product of its (nonzero) digits is 157500, while the sum is 42.

The spelling of 15561601557 in words is "fifteen billion, five hundred sixty-one million, six hundred one thousand, five hundred fifty-seven".