221102021 has 4 divisors (see below), whose sum is σ = 252688032. Its totient is φ = 189516012.

The previous prime is 221101981. The next prime is 221102027. The reversal of 221102021 is 120201122.

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 de Polignac number, because none of the positive numbers 2^k-221102021 is a prime.

It is a super-2 number, since 2×221102021² = 97772207380568882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221101993 and 221102011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221102027) 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, 15792995 + ... + 15793008.

It is an arithmetic number, because the mean of its divisors is an integer number (63172008).

Almost surely, 2^221102021 is an apocalyptic number.

It is an amenable number.

221102021 is a deficient number, since it is larger than the sum of its proper divisors (31586011).

221102021 is an equidigital number, since it uses as much as digits as its factorization.

221102021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31586010.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 221102021 is about 14869.4996889606. The cubic root of 221102021 is about 604.6873789560.

Adding to 221102021 its reverse (120201122), we get a palindrome (341303143).

The spelling of 221102021 in words is "two hundred twenty-one million, one hundred two thousand, twenty-one".