51109920 has 96 divisors (see below), whose sum is σ = 178899840. Its totient is φ = 13628160.

The previous prime is 51109907. The next prime is 51109921. The reversal of 51109920 is 2990115.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×51109920² = 5224447844812800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (51109921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1596 + ... + 10235.

It is an arithmetic number, because the mean of its divisors is an integer number (1863540).

Almost surely, 2^51109920 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 51109920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89449920).

51109920 is an abundant number, since it is smaller than the sum of its proper divisors (127789920).

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

51109920 is a wasteful number, since it uses less digits than its factorization.

51109920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11855 (or 11841 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 51109920 is about 7149.1202255942. The cubic root of 51109920 is about 371.1092109762.

The spelling of 51109920 in words is "fifty-one million, one hundred nine thousand, nine hundred twenty".