51218840 has 32 divisors (see below), whose sum is σ = 118056960. Its totient is φ = 19987200.

The previous prime is 51218831. The next prime is 51218873. The reversal of 51218840 is 4881215.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 13976 + ... + 17255.

It is an arithmetic number, because the mean of its divisors is an integer number (3689280).

Almost surely, 2^51218840 is an apocalyptic number.

It is an amenable number.

51218840 is an abundant number, since it is smaller than the sum of its proper divisors (66838120).

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

51218840 is a wasteful number, since it uses less digits than its factorization.

51218840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31283 (or 31279 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 51218840 is about 7156.7338919370. The cubic root of 51218840 is about 371.3726466941.

The spelling of 51218840 in words is "fifty-one million, two hundred eighteen thousand, eight hundred forty".