51121920 has 72 divisors (see below), whose sum is σ = 163282896. Its totient is φ = 13631488.

The previous prime is 51121919. The next prime is 51121933. The reversal of 51121920 is 2912115.

It is a super-2 number, since 2×51121920² = 5226901408972800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2817 + ... + 10496.

It is an arithmetic number, because the mean of its divisors is an integer number (2267818).

Almost surely, 2^51121920 is an apocalyptic number.

It is an amenable number.

51121920 is an abundant number, since it is smaller than the sum of its proper divisors (112160976).

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

51121920 is a wasteful number, since it uses less digits than its factorization.

51121920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13337 (or 13323 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 51121920 is about 7149.9594404444. The cubic root of 51121920 is about 371.1382527098.

The spelling of 51121920 in words is "fifty-one million, one hundred twenty-one thousand, nine hundred twenty".