51791220 has 72 divisors (see below), whose sum is σ = 169192296. Its totient is φ = 12748032.

The previous prime is 51791191. The next prime is 51791263. The reversal of 51791220 is 2219715.

It can be written as a sum of positive squares in 4 ways, for example, as 725904 + 51065316 = 852^2 + 7146^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8727 + ... + 13406.

It is an arithmetic number, because the mean of its divisors is an integer number (2349893).

Almost surely, 2^51791220 is an apocalyptic number.

It is an amenable number.

51791220 is an abundant number, since it is smaller than the sum of its proper divisors (117401076).

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

51791220 is a wasteful number, since it uses less digits than its factorization.

51791220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22161 (or 22156 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 51791220 is about 7196.6117027390. The cubic root of 51791220 is about 372.7509112331.

The spelling of 51791220 in words is "fifty-one million, seven hundred ninety-one thousand, two hundred twenty".