51999864 has 32 divisors (see below), whose sum is σ = 148571520. Its totient is φ = 14857056.

The previous prime is 51999853. The next prime is 51999887. The reversal of 51999864 is 46899915.

51999864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154594 + ... + 154929.

It is an arithmetic number, because the mean of its divisors is an integer number (4642860).

Almost surely, 2^51999864 is an apocalyptic number.

It is an amenable number.

51999864 is an abundant number, since it is smaller than the sum of its proper divisors (96571656).

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

51999864 is a wasteful number, since it uses less digits than its factorization.

51999864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309539 (or 309535 counting only the distinct ones).

The product of its digits is 699840, while the sum is 51.

The square root of 51999864 is about 7211.0931210185. The cubic root of 51999864 is about 373.2507902830.

Adding to 51999864 its sum of digits (51), we get a palindrome (51999915).

The spelling of 51999864 in words is "fifty-one million, nine hundred ninety-nine thousand, eight hundred sixty-four".