51917985 has 48 divisors (see below), whose sum is σ = 105266304. Its totient is φ = 23175936.

The previous prime is 51917977. The next prime is 51918001. The reversal of 51917985 is 58971915.

It is not a de Polignac number, because 51917985 - 2³ = 51917977 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 51917985.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11629 + ... + 15461.

It is an arithmetic number, because the mean of its divisors is an integer number (2193048).

Almost surely, 2^51917985 is an apocalyptic number.

It is an amenable number.

51917985 is an abundant number, since it is smaller than the sum of its proper divisors (53348319).

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

51917985 is a wasteful number, since it uses less digits than its factorization.

51917985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3894 (or 3891 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 51917985 is about 7205.4135897948. The cubic root of 51917985 is about 373.0547804360.

The spelling of 51917985 in words is "fifty-one million, nine hundred seventeen thousand, nine hundred eighty-five".