51815994 has 8 divisors (see below), whose sum is σ = 103632000. Its totient is φ = 17271996.

The previous prime is 51815993. The next prime is 51815999. The reversal of 51815994 is 49951815.

51815994 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

51815994 is an admirable number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51815993) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4317994 + ... + 4318005.

It is an arithmetic number, because the mean of its divisors is an integer number (12954000).

Almost surely, 2^51815994 is an apocalyptic number.

51815994 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

51815994 is a wasteful number, since it uses less digits than its factorization.

51815994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8636004.

The product of its digits is 64800, while the sum is 42.

The square root of 51815994 is about 7198.3327236243. The cubic root of 51815994 is about 372.8103360999.

It can be divided in two parts, 5181 and 5994, that added together give a triangular number (11175 = T₁₄₉).

The spelling of 51815994 in words is "fifty-one million, eight hundred fifteen thousand, nine hundred ninety-four".