21132023221 has 4 divisors (see below), whose sum is σ = 21136972972. Its totient is φ = 21127073472.

The previous prime is 21132023219. The next prime is 21132023233. The reversal of 21132023221 is 12232023112.

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 14282640100 + 6849383121 = 119510^2 + 82761^2 .

It is a cyclic number.

It is not a de Polignac number, because 21132023221 - 2¹ = 21132023219 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 (21132023201) 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, 2468466 + ... + 2477011.

It is an arithmetic number, because the mean of its divisors is an integer number (5284243243).

Almost surely, 2^21132023221 is an apocalyptic number.

It is an amenable number.

21132023221 is a deficient number, since it is larger than the sum of its proper divisors (4949751).

21132023221 is an equidigital number, since it uses as much as digits as its factorization.

21132023221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4949750.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21132023221 its reverse (12232023112), we get a palindrome (33364046333).

The spelling of 21132023221 in words is "twenty-one billion, one hundred thirty-two million, twenty-three thousand, two hundred twenty-one".