21101230021 has 4 divisors (see below), whose sum is σ = 21355461792. Its totient is φ = 20846998252.

The previous prime is 21101230019. The next prime is 21101230063. The reversal of 21101230021 is 12003210112.

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 21101230021 - 2¹ = 21101230019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101229983 and 21101230010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101230081) 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, 127115761 + ... + 127115926.

It is an arithmetic number, because the mean of its divisors is an integer number (5338865448).

Almost surely, 2^21101230021 is an apocalyptic number.

It is an amenable number.

21101230021 is a deficient number, since it is larger than the sum of its proper divisors (254231771).

21101230021 is an equidigital number, since it uses as much as digits as its factorization.

21101230021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254231770.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21101230021 its reverse (12003210112), we get a palindrome (33104440133).

The spelling of 21101230021 in words is "twenty-one billion, one hundred one million, two hundred thirty thousand, twenty-one".