51557631 has 4 divisors (see below), whose sum is σ = 68743512. Its totient is φ = 34371752.

The previous prime is 51557603. The next prime is 51557641. The reversal of 51557631 is 13675515.

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

It is a cyclic number.

It is not a de Polignac number, because 51557631 - 2⁶ = 51557567 is a prime.

It is a super-2 number, since 2×51557631² = 5316378628664322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51557592 and 51557601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51557641) 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, 8592936 + ... + 8592941.

It is an arithmetic number, because the mean of its divisors is an integer number (17185878).

Almost surely, 2^51557631 is an apocalyptic number.

51557631 is a deficient number, since it is larger than the sum of its proper divisors (17185881).

51557631 is a wasteful number, since it uses less digits than its factorization.

51557631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17185880.

The product of its digits is 15750, while the sum is 33.

The square root of 51557631 is about 7180.3642665258. The cubic root of 51557631 is about 372.1896723234.

The spelling of 51557631 in words is "fifty-one million, five hundred fifty-seven thousand, six hundred thirty-one".