51315557 has 4 divisors (see below), whose sum is σ = 51418080. Its totient is φ = 51213036.

The previous prime is 51315547. The next prime is 51315613. The reversal of 51315557 is 75551315.

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 51315557 - 2⁸ = 51315301 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 (51315547) 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, 50507 + ... + 51512.

It is an arithmetic number, because the mean of its divisors is an integer number (12854520).

Almost surely, 2^51315557 is an apocalyptic number.

It is an amenable number.

51315557 is a deficient number, since it is larger than the sum of its proper divisors (102523).

51315557 is a wasteful number, since it uses less digits than its factorization.

51315557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102522.

The product of its digits is 13125, while the sum is 32.

The square root of 51315557 is about 7163.4877678405. The cubic root of 51315557 is about 371.6062551595.

The spelling of 51315557 in words is "fifty-one million, three hundred fifteen thousand, five hundred fifty-seven".