51456681 has 64 divisors (see below), whose sum is σ = 85155840. Its totient is φ = 30602880.

The previous prime is 51456653. The next prime is 51456689. The reversal of 51456681 is 18665415.

51456681 is a `hidden beast` number, since 5 + 14 + 566 + 81 = 666.

It is not a de Polignac number, because 51456681 - 2⁵ = 51456649 is a prime.

It is a super-2 number, since 2×51456681² = 5295580039071522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51456689) 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, 1094800 + ... + 1094846.

It is an arithmetic number, because the mean of its divisors is an integer number (1330560).

Almost surely, 2^51456681 is an apocalyptic number.

It is an amenable number.

51456681 is a deficient number, since it is larger than the sum of its proper divisors (33699159).

51456681 is a wasteful number, since it uses less digits than its factorization.

51456681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163 (or 157 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 51456681 is about 7173.3312345102. The cubic root of 51456681 is about 371.9465974330.

The spelling of 51456681 in words is "fifty-one million, four hundred fifty-six thousand, six hundred eighty-one".