221988 has 24 divisors (see below), whose sum is σ = 558208. Its totient is φ = 68256.

The previous prime is 221987. The next prime is 221989. The reversal of 221988 is 889122.

It is an interprime number because it is at equal distance from previous prime (221987) and next prime (221989).

It is not an unprimeable number, because it can be changed into a prime (221987) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 556 + ... + 867.

2²²¹⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

221988 is an abundant number, since it is smaller than the sum of its proper divisors (336220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221988 is a wasteful number, since it uses less digits than its factorization.

221988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1443 (or 1441 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 221988 is about 471.1560251127. The cubic root of 221988 is about 60.5493984456.

The spelling of 221988 in words is "two hundred twenty-one thousand, nine hundred eighty-eight".