721591960321 has 4 divisors (see below), whose sum is σ = 721593921492. Its totient is φ = 721589999152.

The previous prime is 721591960277. The next prime is 721591960361. The reversal of 721591960321 is 123069195127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 340052259600 + 381539700721 = 583140^2 + 617689^2 .

It is a cyclic number.

It is not a de Polignac number, because 721591960321 - 2³⁷ = 584153006849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721591960361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 244486 + ... + 1225951.

It is an arithmetic number, because the mean of its divisors is an integer number (180398480373).

Almost surely, 2^721591960321 is an apocalyptic number.

It is an amenable number.

721591960321 is a deficient number, since it is larger than the sum of its proper divisors (1961171).

721591960321 is a wasteful number, since it uses less digits than its factorization.

721591960321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1961170.

The product of its (nonzero) digits is 204120, while the sum is 46.

The spelling of 721591960321 in words is "seven hundred twenty-one billion, five hundred ninety-one million, nine hundred sixty thousand, three hundred twenty-one".