51915881 has 4 divisors (see below), whose sum is σ = 53182164. Its totient is φ = 50649600.

The previous prime is 51915869. The next prime is 51915883. The reversal of 51915881 is 18851915.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19891600 + 32024281 = 4460^2 + 5659^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51915881 is a prime.

It is a super-2 number, since 2×51915881² = 5390517400012322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51915883) 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 3 ways as a sum of consecutive naturals, for example, 633080 + ... + 633161.

It is an arithmetic number, because the mean of its divisors is an integer number (13295541).

Almost surely, 2^51915881 is an apocalyptic number.

It is an amenable number.

51915881 is a deficient number, since it is larger than the sum of its proper divisors (1266283).

51915881 is a wasteful number, since it uses less digits than its factorization.

51915881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266282.

The product of its digits is 14400, while the sum is 38.

The square root of 51915881 is about 7205.2675869811. The cubic root of 51915881 is about 373.0497409629.

The spelling of 51915881 in words is "fifty-one million, nine hundred fifteen thousand, eight hundred eighty-one".