221901 has 16 divisors (see below), whose sum is σ = 331200. Its totient is φ = 131328.

The previous prime is 221891. The next prime is 221909. The reversal of 221901 is 109122.

221901 = T₁₅₃ + T₁₅₄ + ... + T₁₆₉.

221901 = 153² + 154² + ... + 161².

It is a happy number.

It is not a de Polignac number, because 221901 - 2⁷ = 221773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 855 + ... + 1083.

It is an arithmetic number, because the mean of its divisors is an integer number (20700).

2²²¹⁹⁰¹ is an apocalyptic number.

It is an amenable number.

221901 is a deficient number, since it is larger than the sum of its proper divisors (109299).

221901 is a wasteful number, since it uses less digits than its factorization.

221901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 221901 is about 471.0636899613. The cubic root of 221901 is about 60.5414873784.

The spelling of 221901 in words is "two hundred twenty-one thousand, nine hundred one".