51665400 has 72 divisors (see below), whose sum is σ = 173515680. Its totient is φ = 13776960.

The previous prime is 51665399. The next prime is 51665413. The reversal of 51665400 is 456615.

It is a happy number.

51665400 is a `hidden beast` number, since 5 + 1 + 6 + 654 + 0 + 0 = 666.

51665400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (72).

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 17 ways as a sum of consecutive naturals, for example, 12552 + ... + 16151.

It is an arithmetic number, because the mean of its divisors is an integer number (2409940).

Almost surely, 2^51665400 is an apocalyptic number.

51665400 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51665400 is an abundant number, since it is smaller than the sum of its proper divisors (121850280).

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

51665400 is a wasteful number, since it uses less digits than its factorization.

51665400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28725 (or 28713 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 51665400 is about 7187.8647733524. The cubic root of 51665400 is about 372.4488165940.

The spelling of 51665400 in words is "fifty-one million, six hundred sixty-five thousand, four hundred".