21122021021021 has 8 divisors (see below), whose sum is σ = 21850609102200. Its totient is φ = 20393449108480.

The previous prime is 21122021021009. The next prime is 21122021021047. The reversal of 21122021021021 is 12012012022112.

It can be written as a sum of positive squares in 4 ways, for example, as 13714838256025 + 7407182764996 = 3703355^2 + 2721614^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21122021021021 - 2⁶ = 21122021020957 is a prime.

It is a super-2 number, since 2×21122021021021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122021021071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1354076 + ... + 6639093.

It is an arithmetic number, because the mean of its divisors is an integer number (2731326137775).

Almost surely, 2^{21122021021021} is an apocalyptic number.

It is an amenable number.

21122021021021 is a deficient number, since it is larger than the sum of its proper divisors (728588081179).

21122021021021 is an equidigital number, since it uses as much as digits as its factorization.

21122021021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8084319.

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

Adding to 21122021021021 its reverse (12012012022112), we get a palindrome (33134033043133).

The spelling of 21122021021021 in words is "twenty-one trillion, one hundred twenty-two billion, twenty-one million, twenty-one thousand, twenty-one".