221879623681 has 3 divisors (see below), whose sum is σ = 221880094723. Its totient is φ = 221879152640.

The previous prime is 221879623661. The next prime is 221879623687. The reversal of 221879623681 is 186326978122.

The square root of 221879623681 is 471041.

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 can be written as a sum of positive squares in only one way, i.e., 203437983681 + 18441640000 = 451041^2 + 135800^2 .

It is not a de Polignac number, because 221879623681 - 2¹⁵ = 221879590913 is a prime.

It is a super-2 number, since 2×221879623681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221879623687) 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, 235521 + ... + 706561.

Almost surely, 2^221879623681 is an apocalyptic number.

221879623681 is the 471041-st square number.

221879623681 is the 235521-st centered octagonal number.

It is an amenable number.

221879623681 is a deficient number, since it is larger than the sum of its proper divisors (471042).

221879623681 is an frugal number, since it uses more digits than its factorization.

221879623681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 942082 (or 471041 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 55.

The spelling of 221879623681 in words is "two hundred twenty-one billion, eight hundred seventy-nine million, six hundred twenty-three thousand, six hundred eighty-one".