21221201201021 has 4 divisors (see below), whose sum is σ = 21408999441852. Its totient is φ = 21033402960192.

The previous prime is 21221201201003. The next prime is 21221201201041. The reversal of 21221201201021 is 12010210212212.

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 164905027225 + 21056296173796 = 406085^2 + 4588714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221201201021 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 (21221201201041) 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, 93899120246 + ... + 93899120471.

It is an arithmetic number, because the mean of its divisors is an integer number (5352249860463).

Almost surely, 2^{21221201201021} is an apocalyptic number.

It is an amenable number.

21221201201021 is a deficient number, since it is larger than the sum of its proper divisors (187798240831).

21221201201021 is a wasteful number, since it uses less digits than its factorization.

21221201201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187798240830.

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

Adding to 21221201201021 its reverse (12010210212212), we get a palindrome (33231411413233).

The spelling of 21221201201021 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred one thousand, twenty-one".