721329174721 has 3 divisors (see below), whose sum is σ = 721330024033. Its totient is φ = 721328325410.

The previous prime is 721329174719. The next prime is 721329174739. The reversal of 721329174721 is 127471923127.

The square root of 721329174721 is 849311.

It is a perfect power (a square), and thus also a powerful number.

721329174721 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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 127471923127 = 19763 ⋅6450029.

It is not a de Polignac number, because 721329174721 - 2¹ = 721329174719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721329174121) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 424656 + ... + 1273966.

Almost surely, 2^721329174721 is an apocalyptic number.

721329174721 is the 849311-st square number.

721329174721 is the 424656-th centered octagonal number.

It is an amenable number.

721329174721 is a deficient number, since it is larger than the sum of its proper divisors (849312).

721329174721 is an frugal number, since it uses more digits than its factorization.

721329174721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1698622 (or 849311 counting only the distinct ones).

The product of its digits is 296352, while the sum is 46.

The spelling of 721329174721 in words is "seven hundred twenty-one billion, three hundred twenty-nine million, one hundred seventy-four thousand, seven hundred twenty-one".