221890 has 8 divisors (see below), whose sum is σ = 399420. Its totient is φ = 88752.

The previous prime is 221873. The next prime is 221891. The reversal of 221890 is 98122.

It can be written as a sum of positive squares in 2 ways, for example, as 221841 + 49 = 471^2 + 7^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (221891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11085 + ... + 11104.

2²²¹⁸⁹⁰ is an apocalyptic number.

221890 is a deficient number, since it is larger than the sum of its proper divisors (177530).

221890 is a wasteful number, since it uses less digits than its factorization.

221890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22196.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 221890 is about 471.0520141131. The cubic root of 221890 is about 60.5404869813.

It can be divided in two parts, 221 and 890, that added together give a palindrome (1111).

The spelling of 221890 in words is "two hundred twenty-one thousand, eight hundred ninety".