221990 has 16 divisors (see below), whose sum is σ = 406080. Its totient is φ = 87360.

The previous prime is 221989. The next prime is 221999. The reversal of 221990 is 99122.

221990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221999) 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, 650 + ... + 930.

It is an arithmetic number, because the mean of its divisors is an integer number (25380).

2²²¹⁹⁹⁰ is an apocalyptic number.

221990 is a deficient number, since it is larger than the sum of its proper divisors (184090).

221990 is a wasteful number, since it uses less digits than its factorization.

221990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 221990 is about 471.1581475471. The cubic root of 221990 is about 60.5495802850.

The spelling of 221990 in words is "two hundred twenty-one thousand, nine hundred ninety".