721621607 has 16 divisors (see below), whose sum is σ = 851038272. Its totient is φ = 599009280.

The previous prime is 721621603. The next prime is 721621633. The reversal of 721621607 is 706126127.

It is a cyclic number.

It is not a de Polignac number, because 721621607 - 2² = 721621603 is a prime.

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

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30143 + ... + 48495.

It is an arithmetic number, because the mean of its divisors is an integer number (53189892).

Almost surely, 2^721621607 is an apocalyptic number.

721621607 is a deficient number, since it is larger than the sum of its proper divisors (129416665).

721621607 is a wasteful number, since it uses less digits than its factorization.

721621607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18538.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 721621607 is about 26863.0155976577. The cubic root of 721621607 is about 896.9533223122.

The spelling of 721621607 in words is "seven hundred twenty-one million, six hundred twenty-one thousand, six hundred seven".