21131212232021 has 8 divisors (see below), whose sum is σ = 21145258575000. Its totient is φ = 21117166950400.

The previous prime is 21131212231991. The next prime is 21131212232023. The reversal of 21131212232021 is 12023221213112.

It can be written as a sum of positive squares in 4 ways, for example, as 17105627451025 + 4025584780996 = 4135895^2 + 2006386^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21131212232021 - 2²² = 21131208037717 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 (21131212232023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41773235 + ... + 42276063.

It is an arithmetic number, because the mean of its divisors is an integer number (2643157321875).

Almost surely, 2^{21131212232021} is an apocalyptic number.

It is an amenable number.

21131212232021 is a deficient number, since it is larger than the sum of its proper divisors (14046342979).

21131212232021 is a wasteful number, since it uses less digits than its factorization.

21131212232021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530679.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21131212232021 its reverse (12023221213112), we get a palindrome (33154433445133).

The spelling of 21131212232021 in words is "twenty-one trillion, one hundred thirty-one billion, two hundred twelve million, two hundred thirty-two thousand, twenty-one".