221790 has 16 divisors (see below), whose sum is σ = 532368. Its totient is φ = 59136.

The previous prime is 221773. The next prime is 221797. The reversal of 221790 is 97122.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3667 + ... + 3726.

It is an arithmetic number, because the mean of its divisors is an integer number (33273).

2²²¹⁷⁹⁰ is an apocalyptic number.

221790 is an abundant number, since it is smaller than the sum of its proper divisors (310578).

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

221790 is a wasteful number, since it uses less digits than its factorization.

221790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7403.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 221790 is about 470.9458567606. The cubic root of 221790 is about 60.5313909451.

The spelling of 221790 in words is "two hundred twenty-one thousand, seven hundred ninety".