51331566 has 64 divisors (see below), whose sum is σ = 124830720. Its totient is φ = 13856640.

The previous prime is 51331513. The next prime is 51331573. The reversal of 51331566 is 66513315.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23851 + ... + 25913.

It is an arithmetic number, because the mean of its divisors is an integer number (1950480).

Almost surely, 2^51331566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51331566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62415360).

51331566 is an abundant number, since it is smaller than the sum of its proper divisors (73499154).

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

51331566 is a wasteful number, since it uses less digits than its factorization.

51331566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121.

The product of its digits is 8100, while the sum is 30.

The square root of 51331566 is about 7164.6050833246. The cubic root of 51331566 is about 371.6448946830.

The spelling of 51331566 in words is "fifty-one million, three hundred thirty-one thousand, five hundred sixty-six".