21102231021 has 4 divisors (see below), whose sum is σ = 28136308032. Its totient is φ = 14068154012.

The previous prime is 21102231013. The next prime is 21102231043. The reversal of 21102231021 is 12013220112.

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 21102231021 - 2³ = 21102231013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102231011) 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, 3517038501 + ... + 3517038506.

It is an arithmetic number, because the mean of its divisors is an integer number (7034077008).

Almost surely, 2^21102231021 is an apocalyptic number.

It is an amenable number.

21102231021 is a deficient number, since it is larger than the sum of its proper divisors (7034077011).

21102231021 is an equidigital number, since it uses as much as digits as its factorization.

21102231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7034077010.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21102231021 its reverse (12013220112), we get a palindrome (33115451133).

The spelling of 21102231021 in words is "twenty-one billion, one hundred two million, two hundred thirty-one thousand, twenty-one".