51616615561 has 16 divisors (see below), whose sum is σ = 60297431040. Its totient is φ = 43264175760.

The previous prime is 51616615553. The next prime is 51616615579. The reversal of 51616615561 is 16551661615.

It is a cyclic number.

It is not a de Polignac number, because 51616615561 - 2³ = 51616615553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51616615861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 318270 + ... + 452248.

It is an arithmetic number, because the mean of its divisors is an integer number (3768589440).

Almost surely, 2^51616615561 is an apocalyptic number.

It is an amenable number.

51616615561 is a deficient number, since it is larger than the sum of its proper divisors (8680815479).

51616615561 is a wasteful number, since it uses less digits than its factorization.

51616615561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135204.

The product of its digits is 162000, while the sum is 43.

The spelling of 51616615561 in words is "fifty-one billion, six hundred sixteen million, six hundred fifteen thousand, five hundred sixty-one".