51257820 has 48 divisors (see below), whose sum is σ = 151079040. Its totient is φ = 12949056.

The previous prime is 51257813. The next prime is 51257851. The reversal of 51257820 is 2875215.

It is a super-2 number, since 2×51257820² = 5254728222304800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21342 + ... + 23621.

It is an arithmetic number, because the mean of its divisors is an integer number (3147480).

Almost surely, 2^51257820 is an apocalyptic number.

It is an amenable number.

51257820 is an abundant number, since it is smaller than the sum of its proper divisors (99821220).

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

51257820 is a wasteful number, since it uses less digits than its factorization.

51257820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44994 (or 44992 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 51257820 is about 7159.4566832966. The cubic root of 51257820 is about 371.4668336182.

The spelling of 51257820 in words is "fifty-one million, two hundred fifty-seven thousand, eight hundred twenty".