21021001202021 has 4 divisors (see below), whose sum is σ = 21021166496544. Its totient is φ = 21020835907500.

The previous prime is 21021001201969. The next prime is 21021001202057. The reversal of 21021001202021 is 12020210012012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021001202021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021001201987 and 21021001202005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021001202081) 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, 82456355 + ... + 82710896.

It is an arithmetic number, because the mean of its divisors is an integer number (5255291624136).

Almost surely, 2^{21021001202021} is an apocalyptic number.

It is an amenable number.

21021001202021 is a deficient number, since it is larger than the sum of its proper divisors (165294523).

21021001202021 is a wasteful number, since it uses less digits than its factorization.

21021001202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165294522.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21021001202021 its reverse (12020210012012), we get a palindrome (33041211214033).

The spelling of 21021001202021 in words is "twenty-one trillion, twenty-one billion, one million, two hundred two thousand, twenty-one".