221213111021 has 16 divisors (see below), whose sum is σ = 256565447424. Its totient is φ = 186817083264.

The previous prime is 221213110967. The next prime is 221213111033. The reversal of 221213111021 is 120111312122.

It is a happy number.

It is not a de Polignac number, because 221213111021 - 2³⁴ = 204033241837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221213111051) 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, 636680 + ... + 920753.

It is an arithmetic number, because the mean of its divisors is an integer number (16035340464).

Almost surely, 2^221213111021 is an apocalyptic number.

It is an amenable number.

221213111021 is a deficient number, since it is larger than the sum of its proper divisors (35352336403).

221213111021 is a wasteful number, since it uses less digits than its factorization.

221213111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557740.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 221213111021 its reverse (120111312122), we get a palindrome (341324423143).

The spelling of 221213111021 in words is "two hundred twenty-one billion, two hundred thirteen million, one hundred eleven thousand, twenty-one".