51813920 has 24 divisors (see below), whose sum is σ = 122410764. Its totient is φ = 20725504.

The previous prime is 51813911. The next prime is 51813929. The reversal of 51813920 is 2931815.

It is an interprime number because it is at equal distance from previous prime (51813911) and next prime (51813929).

It can be written as a sum of positive squares in 2 ways, for example, as 49392784 + 2421136 = 7028^2 + 1556^2 .

It is not an unprimeable number, because it can be changed into a prime (51813929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161759 + ... + 162078.

Almost surely, 2^51813920 is an apocalyptic number.

It is an amenable number.

51813920 is an abundant number, since it is smaller than the sum of its proper divisors (70596844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51813920 is a wasteful number, since it uses less digits than its factorization.

51813920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323852 (or 323844 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 51813920 is about 7198.1886610452. The cubic root of 51813920 is about 372.8053619668.

The spelling of 51813920 in words is "fifty-one million, eight hundred thirteen thousand, nine hundred twenty".