221020122110021 has 4 divisors (see below), whose sum is σ = 238021669964652. Its totient is φ = 204018574255392.

The previous prime is 221020122110017. The next prime is 221020122110063. The reversal of 221020122110021 is 120011221020122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20342129550625 + 200677992559396 = 4510225^2 + 14166086^2 .

It is not a de Polignac number, because 221020122110021 - 2² = 221020122110017 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 (221020122310021) 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, 8500773927296 + ... + 8500773927321.

It is an arithmetic number, because the mean of its divisors is an integer number (59505417491163).

Almost surely, 2^{221020122110021} is an apocalyptic number.

It is an amenable number.

221020122110021 is a deficient number, since it is larger than the sum of its proper divisors (17001547854631).

221020122110021 is a wasteful number, since it uses less digits than its factorization.

221020122110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17001547854630.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 221020122110021 its reverse (120011221020122), we get a palindrome (341031343130143).

The spelling of 221020122110021 in words is "two hundred twenty-one trillion, twenty billion, one hundred twenty-two million, one hundred ten thousand, twenty-one".