51931 has 4 divisors (see below), whose sum is σ = 56664. Its totient is φ = 47200.

The previous prime is 51929. The next prime is 51941. The reversal of 51931 is 13915.

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 51931 - 2¹ = 51929 is a prime.

It is a super-2 number, since 2×51931² = 5393657522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51899 and 51908.

It is not an unprimeable number, because it can be changed into a prime (51941) 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, 2350 + ... + 2371.

It is an arithmetic number, because the mean of its divisors is an integer number (14166).

2⁵¹⁹³¹ is an apocalyptic number.

51931 is a deficient number, since it is larger than the sum of its proper divisors (4733).

51931 is a wasteful number, since it uses less digits than its factorization.

51931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4732.

The product of its digits is 135, while the sum is 19.

The square root of 51931 is about 227.8837422898. The cubic root of 51931 is about 37.3085950767.

Multiplying 51931 by its sum of digits (19), we get a palindrome (986689).

It can be divided in two parts, 5 and 1931, that added together give a square (1936 = 44²).

The spelling of 51931 in words is "fifty-one thousand, nine hundred thirty-one".