21201212211021 has 12 divisors (see below), whose sum is σ = 31451648145372. Its totient is φ = 13752137650176.

The previous prime is 21201212210939. The next prime is 21201212211103. The reversal of 21201212211021 is 12011221210212.

21201212211021 is a `hidden beast` number, since 21 + 201 + 212 + 211 + 0 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (21201212210939) and next prime (21201212211103).

It can be written as a sum of positive squares in 2 ways, for example, as 12696494009796 + 8504718201225 = 3563214^2 + 2916285^2 .

It is not a de Polignac number, because 21201212211021 - 2¹⁵ = 21201212178253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201212210985 and 21201212211003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201212111021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31833651636 + ... + 31833652301.

It is an arithmetic number, because the mean of its divisors is an integer number (2620970678781).

Almost surely, 2^{21201212211021} is an apocalyptic number.

It is an amenable number.

21201212211021 is a deficient number, since it is larger than the sum of its proper divisors (10250435934351).

21201212211021 is a wasteful number, since it uses less digits than its factorization.

21201212211021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63667303980 (or 63667303977 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21201212211021 its reverse (12011221210212), we get a palindrome (33212433421233).

The spelling of 21201212211021 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred eleven thousand, twenty-one".