21021021021021 has 64 divisors (see below), whose sum is σ = 33996794560512. Its totient is φ = 11299150080000.

The previous prime is 21021021020971. The next prime is 21021021021023. The reversal of 21021021021021 is 12012012012012.

It is not a de Polignac number, because 21021021021021 - 2¹⁴ = 21021021004637 is a prime.

21021021021021 is a modest number, since divided by 21021021 gives 21021 as remainder.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021021021023) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5780181 + ... + 8686341.

It is an arithmetic number, because the mean of its divisors is an integer number (531199915008).

Almost surely, 2^{21021021021021} is an apocalyptic number.

21021021021021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21021021021021 is a deficient number, since it is larger than the sum of its proper divisors (12975773539491).

21021021021021 is a wasteful number, since it uses less digits than its factorization.

21021021021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2906514.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21021021021021 its reverse (12012012012012), we get a palindrome (33033033033033).

Subtracting from 21021021021021 its reverse (12012012012012), we obtain a palindrome (9009009009009).

The spelling of 21021021021021 in words is "twenty-one trillion, twenty-one billion, twenty-one million, twenty-one thousand, twenty-one".