51981688 has 32 divisors (see below), whose sum is σ = 109998000. Its totient is φ = 22812160.

The previous prime is 51981661. The next prime is 51981697. The reversal of 51981688 is 88618915.

51981688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7633 + ... + 12736.

Almost surely, 2^51981688 is an apocalyptic number.

51981688 is a gapful number since it is divisible by the number (58) formed by its first and last digit.

It is an amenable number.

51981688 is an abundant number, since it is smaller than the sum of its proper divisors (58016312).

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

51981688 is a wasteful number, since it uses less digits than its factorization.

51981688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20415 (or 20411 counting only the distinct ones).

The product of its digits is 138240, while the sum is 46.

The square root of 51981688 is about 7209.8327303759. The cubic root of 51981688 is about 373.2072965990.

It can be divided in two parts, 5198 and 1688, that added together give a palindrome (6886).

The spelling of 51981688 in words is "fifty-one million, nine hundred eighty-one thousand, six hundred eighty-eight".