51813931 has 16 divisors (see below), whose sum is σ = 59421600. Its totient is φ = 44782848.

The previous prime is 51813929. The next prime is 51813941. The reversal of 51813931 is 13931815.

It is not a de Polignac number, because 51813931 - 2¹ = 51813929 is a prime.

It is a super-2 number, since 2×51813931² = 5369366891345522, 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 = 51813893 and 51813902.

It is not an unprimeable number, because it can be changed into a prime (51813911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20805 + ... + 23161.

It is an arithmetic number, because the mean of its divisors is an integer number (3713850).

Almost surely, 2^51813931 is an apocalyptic number.

51813931 is a deficient number, since it is larger than the sum of its proper divisors (7607669).

51813931 is a wasteful number, since it uses less digits than its factorization.

51813931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2478.

The product of its digits is 3240, while the sum is 31.

The square root of 51813931 is about 7198.1894251263. The cubic root of 51813931 is about 372.8053883487.

The spelling of 51813931 in words is "fifty-one million, eight hundred thirteen thousand, nine hundred thirty-one".