721864322215 has 4 divisors (see below), whose sum is σ = 866237186664. Its totient is φ = 577491457768.

The previous prime is 721864322189. The next prime is 721864322227. The reversal of 721864322215 is 512223468127.

721864322215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 721864322215 - 2³⁵ = 687504583847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72186432217 + ... + 72186432226.

It is an arithmetic number, because the mean of its divisors is an integer number (216559296666).

Almost surely, 2^721864322215 is an apocalyptic number.

721864322215 is a deficient number, since it is larger than the sum of its proper divisors (144372864449).

721864322215 is a wasteful number, since it uses less digits than its factorization.

721864322215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144372864448.

The product of its digits is 322560, while the sum is 43.

The spelling of 721864322215 in words is "seven hundred twenty-one billion, eight hundred sixty-four million, three hundred twenty-two thousand, two hundred fifteen".