51285681 has 12 divisors (see below), whose sum is σ = 74285952. Its totient is φ = 34095096.

The previous prime is 51285673. The next prime is 51285701. The reversal of 51285681 is 18658215.

51285681 is a `hidden beast` number, since 512 + 85 + 68 + 1 = 666.

51285681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51285681 - 2³ = 51285673 is a prime.

It is a super-2 number, since 2×51285681² = 5260442151267522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51285631) 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 11 ways as a sum of consecutive naturals, for example, 4461 + ... + 11066.

It is an arithmetic number, because the mean of its divisors is an integer number (6190496).

Almost surely, 2^51285681 is an apocalyptic number.

It is an amenable number.

51285681 is a deficient number, since it is larger than the sum of its proper divisors (23000271).

51285681 is a wasteful number, since it uses less digits than its factorization.

51285681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15900 (or 15897 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The square root of 51285681 is about 7161.4021671737. The cubic root of 51285681 is about 371.5341245726.

The spelling of 51285681 in words is "fifty-one million, two hundred eighty-five thousand, six hundred eighty-one".