721621623 has 4 divisors (see below), whose sum is σ = 962162168. Its totient is φ = 481081080.

The previous prime is 721621603. The next prime is 721621633. The reversal of 721621623 is 326126127.

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

It is not a de Polignac number, because 721621623 - 2⁵ = 721621591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721621603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120270268 + ... + 120270273.

It is an arithmetic number, because the mean of its divisors is an integer number (240540542).

Almost surely, 2^721621623 is an apocalyptic number.

721621623 is a deficient number, since it is larger than the sum of its proper divisors (240540545).

721621623 is a wasteful number, since it uses less digits than its factorization.

721621623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240540544.

The product of its digits is 6048, while the sum is 30.

The square root of 721621623 is about 26863.0158954649. The cubic root of 721621623 is about 896.9533289414.

The spelling of 721621623 in words is "seven hundred twenty-one million, six hundred twenty-one thousand, six hundred twenty-three".