21002013212021 has 4 divisors (see below), whose sum is σ = 21076753472844. Its totient is φ = 20927272951200.

The previous prime is 21002013212009. The next prime is 21002013212057. The reversal of 21002013212021 is 12021231020012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12911481495025 + 8090531716996 = 3593255^2 + 2844386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002013212021 - 2¹⁴ = 21002013195637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002013232021) 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, 37370129990 + ... + 37370130551.

It is an arithmetic number, because the mean of its divisors is an integer number (5269188368211).

Almost surely, 2^{21002013212021} is an apocalyptic number.

It is an amenable number.

21002013212021 is a deficient number, since it is larger than the sum of its proper divisors (74740260823).

21002013212021 is an equidigital number, since it uses as much as digits as its factorization.

21002013212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74740260822.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21002013212021 its reverse (12021231020012), we get a palindrome (33023244232033).

The spelling of 21002013212021 in words is "twenty-one trillion, two billion, thirteen million, two hundred twelve thousand, twenty-one".