51690624 has 64 divisors (see below), whose sum is σ = 138140640. Its totient is φ = 17125376.

The previous prime is 51690623. The next prime is 51690641. The reversal of 51690624 is 42609615.

It is a tau number, because it is divible by the number of its divisors (64).

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (51690623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86872 + ... + 87464.

Almost surely, 2^51690624 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 51690624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69070320).

51690624 is an abundant number, since it is smaller than the sum of its proper divisors (86450016).

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

51690624 is a wasteful number, since it uses less digits than its factorization.

51690624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837 (or 825 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 51690624 is about 7189.6191832391. The cubic root of 51690624 is about 372.5094188571.

The spelling of 51690624 in words is "fifty-one million, six hundred ninety thousand, six hundred twenty-four".