51508640 has 96 divisors (see below), whose sum is σ = 133494480. Its totient is φ = 18694144.

The previous prime is 51508631. The next prime is 51508679. The reversal of 51508640 is 4680515.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 23078416 + 28430224 = 4804^2 + 5332^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

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, 78554 + ... + 79206.

Almost surely, 2^51508640 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 51508640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66747240).

51508640 is an abundant number, since it is smaller than the sum of its proper divisors (81985840).

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

51508640 is a wasteful number, since it uses less digits than its factorization.

51508640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 714 (or 706 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 51508640 is about 7176.9519992821. The cubic root of 51508640 is about 372.0717478291.

The spelling of 51508640 in words is "fifty-one million, five hundred eight thousand, six hundred forty".