51687687 has 4 divisors (see below), whose sum is σ = 68916920. Its totient is φ = 34458456.

The previous prime is 51687661. The next prime is 51687689. The reversal of 51687687 is 78678615.

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

It is not a de Polignac number, because 51687687 - 2²⁴ = 34910471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51687689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8614612 + ... + 8614617.

It is an arithmetic number, because the mean of its divisors is an integer number (17229230).

Almost surely, 2^51687687 is an apocalyptic number.

51687687 is a deficient number, since it is larger than the sum of its proper divisors (17229233).

51687687 is a wasteful number, since it uses less digits than its factorization.

51687687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17229232.

The product of its digits is 564480, while the sum is 48.

The square root of 51687687 is about 7189.4149275167. The cubic root of 51687687 is about 372.5023635422.

The spelling of 51687687 in words is "fifty-one million, six hundred eighty-seven thousand, six hundred eighty-seven".