51215881 has 8 divisors (see below), whose sum is σ = 53825024. Its totient is φ = 48671280.

The previous prime is 51215869. The next prime is 51215893. The reversal of 51215881 is 18851215.

51215881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (51215869) and next prime (51215893).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51215881 - 2⁷ = 51215753 is a prime.

It is a super-2 number, since 2×51215881² = 5246132933212322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51215081) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 14505 + ... + 17686.

It is an arithmetic number, because the mean of its divisors is an integer number (6728128).

Almost surely, 2^51215881 is an apocalyptic number.

It is an amenable number.

51215881 is a deficient number, since it is larger than the sum of its proper divisors (2609143).

51215881 is a wasteful number, since it uses less digits than its factorization.

51215881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32271.

The product of its digits is 3200, while the sum is 31.

The square root of 51215881 is about 7156.5271605717. The cubic root of 51215881 is about 371.3654949454.

The spelling of 51215881 in words is "fifty-one million, two hundred fifteen thousand, eight hundred eighty-one".