51861687 has 4 divisors (see below), whose sum is σ = 69148920. Its totient is φ = 34574456.

The previous prime is 51861673. The next prime is 51861739. The reversal of 51861687 is 78616815.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51861687 - 2⁴ = 51861671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51861287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8643612 + ... + 8643617.

It is an arithmetic number, because the mean of its divisors is an integer number (17287230).

Almost surely, 2^51861687 is an apocalyptic number.

51861687 is a deficient number, since it is larger than the sum of its proper divisors (17287233).

51861687 is a wasteful number, since it uses less digits than its factorization.

51861687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17287232.

The product of its digits is 80640, while the sum is 42.

The square root of 51861687 is about 7201.5058841884. The cubic root of 51861687 is about 372.9198892612.

The spelling of 51861687 in words is "fifty-one million, eight hundred sixty-one thousand, six hundred eighty-seven".