51313511021 has 4 divisors (see below), whose sum is σ = 51705217344. Its totient is φ = 50921804700.

The previous prime is 51313510999. The next prime is 51313511023. The reversal of 51313511021 is 12011531315.

51313511021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51313511021 - 2³⁴ = 34133641837 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 (51313511023) 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, 195852965 + ... + 195853226.

It is an arithmetic number, because the mean of its divisors is an integer number (12926304336).

Almost surely, 2^51313511021 is an apocalyptic number.

It is an amenable number.

51313511021 is a deficient number, since it is larger than the sum of its proper divisors (391706323).

51313511021 is a wasteful number, since it uses less digits than its factorization.

51313511021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391706322.

The product of its (nonzero) digits is 450, while the sum is 23.

The spelling of 51313511021 in words is "fifty-one billion, three hundred thirteen million, five hundred eleven thousand, twenty-one".