51656220 has 144 divisors (see below), whose sum is σ = 195406848. Its totient is φ = 10730880.

The previous prime is 51656197. The next prime is 51656233. The reversal of 51656220 is 2265615.

51656220 is a `hidden beast` number, since 5 + 1 + 656 + 2 + 2 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11997 + ... + 15723.

It is an arithmetic number, because the mean of its divisors is an integer number (1356992).

Almost surely, 2^51656220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51656220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97703424).

51656220 is an abundant number, since it is smaller than the sum of its proper divisors (143750628).

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

51656220 is a wasteful number, since it uses less digits than its factorization.

51656220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3760 (or 3755 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 51656220 is about 7187.2261686968. The cubic root of 51656220 is about 372.4267561651.

The spelling of 51656220 in words is "fifty-one million, six hundred fifty-six thousand, two hundred twenty".