21021020001021 has 4 divisors (see below), whose sum is σ = 28028026668032. Its totient is φ = 14014013334012.

The previous prime is 21021020001019. The next prime is 21021020001061. The reversal of 21021020001021 is 12010002012012.

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 not a de Polignac number, because 21021020001021 - 2¹ = 21021020001019 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21021020000988 and 21021020001006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021020001061) 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, 3503503333501 + ... + 3503503333506.

It is an arithmetic number, because the mean of its divisors is an integer number (7007006667008).

Almost surely, 2^{21021020001021} is an apocalyptic number.

It is an amenable number.

21021020001021 is a deficient number, since it is larger than the sum of its proper divisors (7007006667011).

21021020001021 is an equidigital number, since it uses as much as digits as its factorization.

21021020001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7007006667010.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21021020001021 its reverse (12010002012012), we get a palindrome (33031022013033).

The spelling of 21021020001021 in words is "twenty-one trillion, twenty-one billion, twenty million, one thousand, twenty-one".