221715731689 has 3 divisors (see below), whose sum is σ = 221716202557. Its totient is φ = 221715260822.

The previous prime is 221715731669. The next prime is 221715731737. The reversal of 221715731689 is 986137517122.

The square root of 221715731689 is 470867.

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

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.

It is not a de Polignac number, because 221715731689 - 2⁷ = 221715731561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221715731609) 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, 235434 + ... + 706300.

Almost surely, 2^221715731689 is an apocalyptic number.

221715731689 is the 470867-th square number.

221715731689 is the 235434-th centered octagonal number.

It is an amenable number.

221715731689 is a deficient number, since it is larger than the sum of its proper divisors (470868).

221715731689 is an frugal number, since it uses more digits than its factorization.

221715731689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941734 (or 470867 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 52.

The spelling of 221715731689 in words is "two hundred twenty-one billion, seven hundred fifteen million, seven hundred thirty-one thousand, six hundred eighty-nine".