51821766 has 24 divisors (see below), whose sum is σ = 113142744. Its totient is φ = 17141280.

The previous prime is 51821747. The next prime is 51821767. The reversal of 51821766 is 66712815.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 51821766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51821767) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8631 + ... + 13346.

It is an arithmetic number, because the mean of its divisors is an integer number (4714281).

Almost surely, 2^51821766 is an apocalyptic number.

51821766 is an abundant number, since it is smaller than the sum of its proper divisors (61320978).

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

51821766 is a wasteful number, since it uses less digits than its factorization.

51821766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22116 (or 22113 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 51821766 is about 7198.7336386340. The cubic root of 51821766 is about 372.8241785527.

The spelling of 51821766 in words is "fifty-one million, eight hundred twenty-one thousand, seven hundred sixty-six".