15665616551 has 16 divisors (see below), whose sum is σ = 17206857696. Its totient is φ = 14174839296.

The previous prime is 15665616521. The next prime is 15665616557. The reversal of 15665616551 is 15561656651.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15665616551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15665616496 and 15665616505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15665616557) 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, 104051 + ... + 205323.

It is an arithmetic number, because the mean of its divisors is an integer number (1075428606).

Almost surely, 2^15665616551 is an apocalyptic number.

15665616551 is a deficient number, since it is larger than the sum of its proper divisors (1541241145).

15665616551 is a wasteful number, since it uses less digits than its factorization.

15665616551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101522.

The product of its digits is 810000, while the sum is 47.

It can be divided in two parts, 15 and 665616551, that added together give a palindrome (665616566).

The spelling of 15665616551 in words is "fifteen billion, six hundred sixty-five million, six hundred sixteen thousand, five hundred fifty-one".