51815520 has 72 divisors (see below), whose sum is σ = 176825376. Its totient is φ = 13817088.

The previous prime is 51815509. The next prime is 51815551. The reversal of 51815520 is 2551815.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×51815520² = 5369696225740800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16552 + ... + 19431.

It is an arithmetic number, because the mean of its divisors is an integer number (2455908).

Almost surely, 2^51815520 is an apocalyptic number.

It is an amenable number.

51815520 is an abundant number, since it is smaller than the sum of its proper divisors (125009856).

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

51815520 is a wasteful number, since it uses less digits than its factorization.

51815520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36004 (or 35993 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The square root of 51815520 is about 7198.2997992582. The cubic root of 51815520 is about 372.8091993039.

It can be divided in two parts, 5181 and 5520, that added together give a palindrome (10701).

The spelling of 51815520 in words is "fifty-one million, eight hundred fifteen thousand, five hundred twenty".