21112232021 has 4 divisors (see below), whose sum is σ = 21136196844. Its totient is φ = 21088267200.

The previous prime is 21112231999. The next prime is 21112232023. The reversal of 21112232021 is 12023221112.

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 14764923121 + 6347308900 = 121511^2 + 79670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112232021 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 (21112232023) 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, 11981090 + ... + 11982851.

It is an arithmetic number, because the mean of its divisors is an integer number (5284049211).

Almost surely, 2^21112232021 is an apocalyptic number.

It is an amenable number.

21112232021 is a deficient number, since it is larger than the sum of its proper divisors (23964823).

21112232021 is an equidigital number, since it uses as much as digits as its factorization.

21112232021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23964822.

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

Adding to 21112232021 its reverse (12023221112), we get a palindrome (33135453133).

The spelling of 21112232021 in words is "twenty-one billion, one hundred twelve million, two hundred thirty-two thousand, twenty-one".