201221220101021 has 4 divisors (see below), whose sum is σ = 203977675170972. Its totient is φ = 198464765031072.

The previous prime is 201221220100891. The next prime is 201221220101107. The reversal of 201221220101021 is 120101022122102.

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 48108165360025 + 153113054740996 = 6936005^2 + 12373886^2 .

It is a cyclic number.

It is not a de Polignac number, because 201221220101021 - 2¹⁴ = 201221220084637 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 (201221220101621) 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, 1378227534866 + ... + 1378227535011.

It is an arithmetic number, because the mean of its divisors is an integer number (50994418792743).

Almost surely, 2^{201221220101021} is an apocalyptic number.

It is an amenable number.

201221220101021 is a deficient number, since it is larger than the sum of its proper divisors (2756455069951).

201221220101021 is an equidigital number, since it uses as much as digits as its factorization.

201221220101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2756455069950.

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

Adding to 201221220101021 its reverse (120101022122102), we get a palindrome (321322242223123).

The spelling of 201221220101021 in words is "two hundred one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred one thousand, twenty-one".