61565015551 has 32 divisors (see below), whose sum is σ = 71773490880. Its totient is φ = 52295153664.

The previous prime is 61565015537. The next prime is 61565015557. The reversal of 61565015551 is 15551056516.

It is a de Polignac number, because none of the positive numbers 2^k-61565015551 is a prime.

It is a super-2 number, since 2×61565015551² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61565015557) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3422940 + ... + 3440878.

It is an arithmetic number, because the mean of its divisors is an integer number (2242921590).

Almost surely, 2^61565015551 is an apocalyptic number.

61565015551 is a deficient number, since it is larger than the sum of its proper divisors (10208475329).

61565015551 is a wasteful number, since it uses less digits than its factorization.

61565015551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18315.

The product of its (nonzero) digits is 112500, while the sum is 40.

The spelling of 61565015551 in words is "sixty-one billion, five hundred sixty-five million, fifteen thousand, five hundred fifty-one".