51681621125 has 16 divisors (see below), whose sum is σ = 64671640176. Its totient is φ = 41234414400.

The previous prime is 51681621109. The next prime is 51681621133. The reversal of 51681621125 is 52112618615.

It can be written as a sum of positive squares in 8 ways, for example, as 23133801604 + 28547819521 = 152098^2 + 168961^2 .

It is not a de Polignac number, because 51681621125 - 2⁴ = 51681621109 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 507602 + ... + 600851.

It is an arithmetic number, because the mean of its divisors is an integer number (4041977511).

Almost surely, 2^51681621125 is an apocalyptic number.

It is an amenable number.

51681621125 is a deficient number, since it is larger than the sum of its proper divisors (12990019051).

51681621125 is a wasteful number, since it uses less digits than its factorization.

51681621125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108841 (or 1108831 counting only the distinct ones).

The product of its digits is 28800, while the sum is 38.

The spelling of 51681621125 in words is "fifty-one billion, six hundred eighty-one million, six hundred twenty-one thousand, one hundred twenty-five".