51388640 has 48 divisors (see below), whose sum is σ = 121836960. Its totient is φ = 20482560.

The previous prime is 51388639. The next prime is 51388663. The reversal of 51388640 is 4688315.

It is a self number, because there is not a number n which added to its sum of digits gives 51388640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81125 + ... + 81755.

It is an arithmetic number, because the mean of its divisors is an integer number (2538270).

Almost surely, 2^51388640 is an apocalyptic number.

It is an amenable number.

51388640 is an abundant number, since it is smaller than the sum of its proper divisors (70448320).

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

51388640 is a wasteful number, since it uses less digits than its factorization.

51388640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155 (or 1147 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 51388640 is about 7168.5870295338. The cubic root of 51388640 is about 371.7825838662.

The spelling of 51388640 in words is "fifty-one million, three hundred eighty-eight thousand, six hundred forty".