201221310021 has 16 divisors (see below), whose sum is σ = 268573009536. Its totient is φ = 134008646976.

The previous prime is 201221310013. The next prime is 201221310029. The reversal of 201221310021 is 120013122102.

It is an interprime number because it is at equal distance from previous prime (201221310013) and next prime (201221310029).

It is not a de Polignac number, because 201221310021 - 2³ = 201221310013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201221310029) 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, 15504291 + ... + 15517263.

It is an arithmetic number, because the mean of its divisors is an integer number (16785813096).

Almost surely, 2^201221310021 is an apocalyptic number.

It is an amenable number.

201221310021 is a deficient number, since it is larger than the sum of its proper divisors (67351699515).

201221310021 is a wasteful number, since it uses less digits than its factorization.

201221310021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17932.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 201221310021 its reverse (120013122102), we get a palindrome (321234432123).

The spelling of 201221310021 in words is "two hundred one billion, two hundred twenty-one million, three hundred ten thousand, twenty-one".