51191920 has 40 divisors (see below), whose sum is σ = 128179296. Its totient is φ = 18901248.

The previous prime is 51191867. The next prime is 51191939. The reversal of 51191920 is 2919115.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×51191920² = 5241225346572800, which contains 22 as substring.

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, 23572 + ... + 25651.

Almost surely, 2^51191920 is an apocalyptic number.

It is an amenable number.

51191920 is an abundant number, since it is smaller than the sum of its proper divisors (76987376).

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

51191920 is a wasteful number, since it uses less digits than its factorization.

51191920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49249 (or 49243 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 51191920 is about 7154.8528985577. The cubic root of 51191920 is about 371.3075723084.

The spelling of 51191920 in words is "fifty-one million, one hundred ninety-one thousand, nine hundred twenty".