51457013621 has 4 divisors (see below), whose sum is σ = 55415245452. Its totient is φ = 47498781792.

The previous prime is 51457013579. The next prime is 51457013627. The reversal of 51457013621 is 12631075415.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8891547025 + 42565466596 = 94295^2 + 206314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51457013621 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 (51457013627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1979115896 + ... + 1979115921.

It is an arithmetic number, because the mean of its divisors is an integer number (13853811363).

Almost surely, 2^51457013621 is an apocalyptic number.

It is an amenable number.

51457013621 is a deficient number, since it is larger than the sum of its proper divisors (3958231831).

51457013621 is a wasteful number, since it uses less digits than its factorization.

51457013621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3958231830.

The product of its (nonzero) digits is 25200, while the sum is 35.

The spelling of 51457013621 in words is "fifty-one billion, four hundred fifty-seven million, thirteen thousand, six hundred twenty-one".