21012013233221 has 4 divisors (see below), whose sum is σ = 21689820111744. Its totient is φ = 20334206354700.

The previous prime is 21012013233209. The next prime is 21012013233223. The reversal of 21012013233221 is 12233231021012.

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 not a de Polignac number, because 21012013233221 - 2²⁶ = 21011946124357 is a prime.

It is a super-2 number, since 2×21012013233221² (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 (21012013233223) 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, 338903439215 + ... + 338903439276.

It is an arithmetic number, because the mean of its divisors is an integer number (5422455027936).

Almost surely, 2^{21012013233221} is an apocalyptic number.

It is an amenable number.

21012013233221 is a deficient number, since it is larger than the sum of its proper divisors (677806878523).

21012013233221 is an equidigital number, since it uses as much as digits as its factorization.

21012013233221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677806878522.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21012013233221 its reverse (12233231021012), we get a palindrome (33245244254233).

The spelling of 21012013233221 in words is "twenty-one trillion, twelve billion, thirteen million, two hundred thirty-three thousand, two hundred twenty-one".