721321552 has 30 divisors (see below), whose sum is σ = 1625735418. Its totient is φ = 309137472.

The previous prime is 721321507. The next prime is 721321571. The reversal of 721321552 is 255123127.

It can be written as a sum of positive squares in only one way, i.e., 609892416 + 111429136 = 24696^2 + 10556^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 721321552.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 459243 + ... + 460810.

Almost surely, 2^721321552 is an apocalyptic number.

It is an amenable number.

721321552 is an abundant number, since it is smaller than the sum of its proper divisors (904413866).

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

721321552 is a wasteful number, since it uses less digits than its factorization.

721321552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920075 (or 920062 counting only the distinct ones).

The product of its digits is 4200, while the sum is 28.

The square root of 721321552 is about 26857.4301078863. The cubic root of 721321552 is about 896.8289853846.

Adding to 721321552 its reverse (255123127), we get a palindrome (976444679).

The spelling of 721321552 in words is "seven hundred twenty-one million, three hundred twenty-one thousand, five hundred fifty-two".