51931566 has 72 divisors (see below), whose sum is σ = 122124600. Its totient is φ = 15941376.

The previous prime is 51931553. The next prime is 51931577. The reversal of 51931566 is 66513915.

51931566 is a `hidden beast` number, since 5 + 1 + 93 + 1 + 566 = 666.

51931566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 51931566.

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 35 ways as a sum of consecutive naturals, for example, 348460 + ... + 348608.

It is an arithmetic number, because the mean of its divisors is an integer number (1696175).

Almost surely, 2^51931566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51931566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61062300).

51931566 is an abundant number, since it is smaller than the sum of its proper divisors (70193034).

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

51931566 is a wasteful number, since it uses less digits than its factorization.

51931566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 238 counting only the distinct ones).

The product of its digits is 24300, while the sum is 36.

The square root of 51931566 is about 7206.3559445811. The cubic root of 51931566 is about 373.0873061928.

The spelling of 51931566 in words is "fifty-one million, nine hundred thirty-one thousand, five hundred sixty-six".