521920728 has 96 divisors (see below), whose sum is σ = 1700524800. Its totient is φ = 141269184.

The previous prime is 521920703. The next prime is 521920739. The reversal of 521920728 is 827029125.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 521920692 and 521920701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17676 + ... + 36827.

It is an arithmetic number, because the mean of its divisors is an integer number (17713800).

Almost surely, 2^521920728 is an apocalyptic number.

It is an amenable number.

521920728 is an abundant number, since it is smaller than the sum of its proper divisors (1178604072).

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

521920728 is a wasteful number, since it uses less digits than its factorization.

521920728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54541 (or 54534 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 521920728 is about 22845.5844311324. The cubic root of 521920728 is about 805.1340275535.

The spelling of 521920728 in words is "five hundred twenty-one million, nine hundred twenty thousand, seven hundred twenty-eight".