51261599917 has 16 divisors (see below), whose sum is σ = 59830009920. Its totient is φ = 43424985600.

The previous prime is 51261599903. The next prime is 51261600041. The reversal of 51261599917 is 71999516215.

It is a cyclic number.

It is not a de Polignac number, because 51261599917 - 2¹⁹ = 51261075629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51261599017) 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, 1997668 + ... + 2023165.

It is an arithmetic number, because the mean of its divisors is an integer number (3739375620).

Almost surely, 2^51261599917 is an apocalyptic number.

It is an amenable number.

51261599917 is a deficient number, since it is larger than the sum of its proper divisors (8568410003).

51261599917 is a wasteful number, since it uses less digits than its factorization.

51261599917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4020924.

The product of its digits is 1530900, while the sum is 55.

The spelling of 51261599917 in words is "fifty-one billion, two hundred sixty-one million, five hundred ninety-nine thousand, nine hundred seventeen".