221679 has 6 divisors (see below), whose sum is σ = 320216. Its totient is φ = 147780.

The previous prime is 221677. The next prime is 221707. The reversal of 221679 is 976122.

It is not a de Polignac number, because 221679 - 2¹ = 221677 is a prime.

It is a Duffinian number.

221679 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12307 + ... + 12324.

2²²¹⁶⁷⁹ is an apocalyptic number.

221679 is a deficient number, since it is larger than the sum of its proper divisors (98537).

221679 is a wasteful number, since it uses less digits than its factorization.

221679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24637 (or 24634 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 221679 is about 470.8279940700. The cubic root of 221679 is about 60.5212911426.

It can be divided in two parts, 221 and 679, that added together give a square (900 = 30²).

The spelling of 221679 in words is "two hundred twenty-one thousand, six hundred seventy-nine".