51331665 has 64 divisors (see below), whose sum is σ = 104601600. Its totient is φ = 21309120.

The previous prime is 51331663. The next prime is 51331667. The reversal of 51331665 is 56613315.

It is an interprime number because it is at equal distance from previous prime (51331663) and next prime (51331667).

It is not a de Polignac number, because 51331665 - 2¹ = 51331663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51331663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 56142 + ... + 57048.

It is an arithmetic number, because the mean of its divisors is an integer number (1634400).

Almost surely, 2^51331665 is an apocalyptic number.

51331665 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51331665 is an abundant number, since it is smaller than the sum of its proper divisors (53269935).

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

51331665 is a wasteful number, since it uses less digits than its factorization.

51331665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 947 (or 933 counting only the distinct ones).

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

The square root of 51331665 is about 7164.6119922854. The cubic root of 51331665 is about 371.6451336056.

The spelling of 51331665 in words is "fifty-one million, three hundred thirty-one thousand, six hundred sixty-five".