51639686 has 8 divisors (see below), whose sum is σ = 88525200. Its totient is φ = 22131288.

The previous prime is 51639683. The next prime is 51639703. The reversal of 51639686 is 68693615.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51639683) 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, 1844261 + ... + 1844288.

It is an arithmetic number, because the mean of its divisors is an integer number (11065650).

Almost surely, 2^51639686 is an apocalyptic number.

51639686 is a deficient number, since it is larger than the sum of its proper divisors (36885514).

51639686 is a wasteful number, since it uses less digits than its factorization.

51639686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3688558.

The product of its digits is 233280, while the sum is 44.

The square root of 51639686 is about 7186.0758415146. The cubic root of 51639686 is about 372.3870167682.

It can be divided in two parts, 51639 and 686, that added together give a palindrome (52325).

The spelling of 51639686 in words is "fifty-one million, six hundred thirty-nine thousand, six hundred eighty-six".