221221210220021 has 24 divisors (see below), whose sum is σ = 253102904259744. Its totient is φ = 191739667980960.

The previous prime is 221221210219957. The next prime is 221221210220063. The reversal of 221221210220021 is 120022012122122.

It is not a de Polignac number, because 221221210220021 - 2⁶ = 221221210219957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221221210219975 and 221221210220002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221210220081) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60130586 + ... + 63703451.

It is an arithmetic number, because the mean of its divisors is an integer number (10545954344156).

Almost surely, 2^{221221210220021} is an apocalyptic number.

It is an amenable number.

221221210220021 is a deficient number, since it is larger than the sum of its proper divisors (31881694039723).

221221210220021 is a wasteful number, since it uses less digits than its factorization.

221221210220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123834401 (or 123834378 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 221221210220021 its reverse (120022012122122), we get a palindrome (341243222342143).

The spelling of 221221210220021 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred ten million, two hundred twenty thousand, twenty-one".