51861985 has 32 divisors (see below), whose sum is σ = 76142592. Its totient is φ = 33100800.

The previous prime is 51861961. The next prime is 51862067. The reversal of 51861985 is 58916815.

It is not a de Polignac number, because 51861985 - 2¹¹ = 51859937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 59664 + ... + 60526.

It is an arithmetic number, because the mean of its divisors is an integer number (2379456).

Almost surely, 2^51861985 is an apocalyptic number.

It is an amenable number.

51861985 is a deficient number, since it is larger than the sum of its proper divisors (24280607).

51861985 is a wasteful number, since it uses less digits than its factorization.

51861985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 993.

The product of its digits is 86400, while the sum is 43.

The square root of 51861985 is about 7201.5265742758. The cubic root of 51861985 is about 372.9206035323.

The spelling of 51861985 in words is "fifty-one million, eight hundred sixty-one thousand, nine hundred eighty-five".