21132012221 has 4 divisors (see below), whose sum is σ = 21132418944. Its totient is φ = 21131605500.

The previous prime is 21132012199. The next prime is 21132012227. The reversal of 21132012221 is 12221023112.

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 21132012221 - 2¹⁴ = 21131995837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21132012221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132012227) 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, 111635 + ... + 233936.

It is an arithmetic number, because the mean of its divisors is an integer number (5283104736).

Almost surely, 2^21132012221 is an apocalyptic number.

It is an amenable number.

21132012221 is a deficient number, since it is larger than the sum of its proper divisors (406723).

21132012221 is an equidigital number, since it uses as much as digits as its factorization.

21132012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406722.

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

Adding to 21132012221 its reverse (12221023112), we get a palindrome (33353035333).

The spelling of 21132012221 in words is "twenty-one billion, one hundred thirty-two million, twelve thousand, two hundred twenty-one".