51313920 has 288 divisors, whose sum is σ = 197793792. Its totient is φ = 11083776.

The previous prime is 51313909. The next prime is 51313949. The reversal of 51313920 is 2931315.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 618199 + ... + 618281.

It is an arithmetic number, because the mean of its divisors is an integer number (686784).

Almost surely, 2^51313920 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 51313920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98896896).

51313920 is an abundant number, since it is smaller than the sum of its proper divisors (146479872).

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

51313920 is a wasteful number, since it uses less digits than its factorization.

51313920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 51313920 is about 7163.3735069449. The cubic root of 51313920 is about 371.6023036229.

The spelling of 51313920 in words is "fifty-one million, three hundred thirteen thousand, nine hundred twenty".