51631440 has 160 divisors (see below), whose sum is σ = 185869056. Its totient is φ = 11612160.

The previous prime is 51631357. The next prime is 51631457. The reversal of 51631440 is 4413615.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 51631440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 122430 + ... + 122850.

Almost surely, 2^51631440 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 51631440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92934528).

51631440 is an abundant number, since it is smaller than the sum of its proper divisors (134237616).

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

51631440 is a wasteful number, since it uses less digits than its factorization.

51631440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517 (or 511 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 51631440 is about 7185.5020701410. The cubic root of 51631440 is about 372.3671943729.

The spelling of 51631440 in words is "fifty-one million, six hundred thirty-one thousand, four hundred forty".