51855220 has 12 divisors (see below), whose sum is σ = 108896004. Its totient is φ = 20742080.

The previous prime is 51855191. The next prime is 51855239. The reversal of 51855220 is 2255815.

It can be written as a sum of positive squares in 2 ways, for example, as 36457444 + 15397776 = 6038^2 + 3924^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1296361 + ... + 1296400.

It is an arithmetic number, because the mean of its divisors is an integer number (9074667).

Almost surely, 2^51855220 is an apocalyptic number.

It is an amenable number.

51855220 is an abundant number, since it is smaller than the sum of its proper divisors (57040784).

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

51855220 is a wasteful number, since it uses less digits than its factorization.

51855220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2592770 (or 2592768 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 28.

The square root of 51855220 is about 7201.0568668773. The cubic root of 51855220 is about 372.9043879454.

The spelling of 51855220 in words is "fifty-one million, eight hundred fifty-five thousand, two hundred twenty".