51820720 has 160 divisors (see below), whose sum is σ = 147240576. Its totient is φ = 16588800.

The previous prime is 51820687. The next prime is 51820721. The reversal of 51820720 is 2702815.

It is not an unprimeable number, because it can be changed into a prime (51820721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 849490 + ... + 849550.

Almost surely, 2^51820720 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 51820720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73620288).

51820720 is an abundant number, since it is smaller than the sum of its proper divisors (95419856).

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

51820720 is a wasteful number, since it uses less digits than its factorization.

51820720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 51820720 is about 7198.6609866002. The cubic root of 51820720 is about 372.8216701041.

The spelling of 51820720 in words is "fifty-one million, eight hundred twenty thousand, seven hundred twenty".