51820018 has 4 divisors (see below), whose sum is σ = 77730030. Its totient is φ = 25910008.

The previous prime is 51820009. The next prime is 51820037. The reversal of 51820018 is 81002815.

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

It can be written as a sum of positive squares in only one way, i.e., 46607929 + 5212089 = 6827^2 + 2283^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51819974 and 51820001.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12955003 + ... + 12955006.

Almost surely, 2^51820018 is an apocalyptic number.

51820018 is a deficient number, since it is larger than the sum of its proper divisors (25910012).

51820018 is a wasteful number, since it uses less digits than its factorization.

51820018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25910011.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 51820018 is about 7198.6122273672. The cubic root of 51820018 is about 372.8199865948.

The spelling of 51820018 in words is "fifty-one million, eight hundred twenty thousand, eighteen".