221023221 has 4 divisors (see below), whose sum is σ = 294697632. Its totient is φ = 147348812.

The previous prime is 221023217. The next prime is 221023241. The reversal of 221023221 is 122320122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221023221 - 2² = 221023217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221023221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221023241) 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, 36837201 + ... + 36837206.

It is an arithmetic number, because the mean of its divisors is an integer number (73674408).

Almost surely, 2^221023221 is an apocalyptic number.

It is an amenable number.

221023221 is a deficient number, since it is larger than the sum of its proper divisors (73674411).

221023221 is an equidigital number, since it uses as much as digits as its factorization.

221023221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73674410.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 221023221 is about 14866.8497335515. The cubic root of 221023221 is about 604.6155342527.

Adding to 221023221 its reverse (122320122), we get a palindrome (343343343).

It can be divided in two parts, 2210232 and 21, that added together give a triangular number (2210253 = T₂₁₀₂).

The spelling of 221023221 in words is "two hundred twenty-one million, twenty-three thousand, two hundred twenty-one".