51461865 has 128 divisors (see below), whose sum is σ = 116121600. Its totient is φ = 21047040.

The previous prime is 51461819. The next prime is 51461867. The reversal of 51461865 is 56816415.

51461865 is a `hidden beast` number, since 514 + 61 + 86 + 5 = 666.

It is not a de Polignac number, because 51461865 - 2⁶ = 51461801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51461867) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 724780 + ... + 724850.

It is an arithmetic number, because the mean of its divisors is an integer number (907200).

Almost surely, 2^51461865 is an apocalyptic number.

It is an amenable number.

51461865 is an abundant number, since it is smaller than the sum of its proper divisors (64659735).

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

51461865 is a wasteful number, since it uses less digits than its factorization.

51461865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 158 counting only the distinct ones).

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

The square root of 51461865 is about 7173.6925638056. The cubic root of 51461865 is about 371.9590875922.

It can be divided in two parts, 51461 and 865, that added together give a triangular number (52326 = T₃₂₃).

The spelling of 51461865 in words is "fifty-one million, four hundred sixty-one thousand, eight hundred sixty-five".