221122220021 has 6 divisors (see below), whose sum is σ = 234894538530. Its totient is φ = 208115030336.

The previous prime is 221122220017. The next prime is 221122220051. The reversal of 221122220021 is 120022221122.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 102472972996 + 118649247025 = 320114^2 + 344455^2 .

It is not a de Polignac number, because 221122220021 - 2² = 221122220017 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221122220051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 382564106 + ... + 382564683.

It is an arithmetic number, because the mean of its divisors is an integer number (39149089755).

Almost surely, 2^221122220021 is an apocalyptic number.

It is an amenable number.

221122220021 is a deficient number, since it is larger than the sum of its proper divisors (13772318509).

221122220021 is an equidigital number, since it uses as much as digits as its factorization.

221122220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765128823 (or 765128806 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 221122220021 its reverse (120022221122), we get a palindrome (341144441143).

The spelling of 221122220021 in words is "two hundred twenty-one billion, one hundred twenty-two million, two hundred twenty thousand, twenty-one".