51666820 has 12 divisors (see below), whose sum is σ = 108500364. Its totient is φ = 20666720.

The previous prime is 51666787. The next prime is 51666821. The reversal of 51666820 is 2866615.

It can be written as a sum of positive squares in 2 ways, for example, as 19766916 + 31899904 = 4446^2 + 5648^2 .

It is not an unprimeable number, because it can be changed into a prime (51666821) 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, 1291651 + ... + 1291690.

It is an arithmetic number, because the mean of its divisors is an integer number (9041697).

Almost surely, 2^51666820 is an apocalyptic number.

It is an amenable number.

51666820 is an abundant number, since it is smaller than the sum of its proper divisors (56833544).

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

51666820 is a wasteful number, since it uses less digits than its factorization.

51666820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2583350 (or 2583348 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 51666820 is about 7187.9635502693. The cubic root of 51666820 is about 372.4522287582.

The spelling of 51666820 in words is "fifty-one million, six hundred sixty-six thousand, eight hundred twenty".