51331840 has 144 divisors (see below), whose sum is σ = 149228352. Its totient is φ = 16515072.

The previous prime is 51331807. The next prime is 51331853. The reversal of 51331840 is 4813315.

It is a super-4 number, since 4×51331840⁴ (a number of 32 digits) contains 4444 as substring.

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, 152152 + ... + 152488.

It is an arithmetic number, because the mean of its divisors is an integer number (1036308).

Almost surely, 2^51331840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51331840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74614176).

51331840 is an abundant number, since it is smaller than the sum of its proper divisors (97896512).

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

51331840 is a wasteful number, since it uses less digits than its factorization.

51331840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382 (or 368 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 51331840 is about 7164.6242050787. The cubic root of 51331840 is about 371.6455559429.

The spelling of 51331840 in words is "fifty-one million, three hundred thirty-one thousand, eight hundred forty".