721398528 has 72 divisors (see below), whose sum is σ = 2133322800. Its totient is φ = 240463872.

The previous prime is 721398527. The next prime is 721398563. The reversal of 721398528 is 825893127.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (721398521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45273 + ... + 59096.

Almost surely, 2^721398528 is an apocalyptic number.

It is an amenable number.

721398528 is an abundant number, since it is smaller than the sum of its proper divisors (1411924272).

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

721398528 is a wasteful number, since it uses less digits than its factorization.

721398528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104394 (or 104374 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 721398528 is about 26858.8631181590. The cubic root of 721398528 is about 896.8608860223.

The spelling of 721398528 in words is "seven hundred twenty-one million, three hundred ninety-eight thousand, five hundred twenty-eight".