721710505 has 8 divisors (see below), whose sum is σ = 867073032. Its totient is φ = 576688128.

The previous prime is 721710467. The next prime is 721710511. The reversal of 721710505 is 505017127.

721710505 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 78428736 + 643281769 = 8856^2 + 25363^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721710505 - 2¹¹ = 721708457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80344 + ... + 88873.

It is an arithmetic number, because the mean of its divisors is an integer number (108384129).

Almost surely, 2^721710505 is an apocalyptic number.

It is an amenable number.

721710505 is a deficient number, since it is larger than the sum of its proper divisors (145362527).

721710505 is a wasteful number, since it uses less digits than its factorization.

721710505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170075.

The product of its (nonzero) digits is 2450, while the sum is 28.

The square root of 721710505 is about 26864.6702008418. The cubic root of 721710505 is about 896.9901532873.

The spelling of 721710505 in words is "seven hundred twenty-one million, seven hundred ten thousand, five hundred five".