21100422121 has 4 divisors (see below), whose sum is σ = 21195043072. Its totient is φ = 21005801172.

The previous prime is 21100422071. The next prime is 21100422131. The reversal of 21100422121 is 12122400112.

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 21100422121 - 2⁹ = 21100421609 is a prime.

It is a super-2 number, since 2×21100422121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100422095 and 21100422104.

It is not an unprimeable number, because it can be changed into a prime (21100422131) 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, 47310141 + ... + 47310586.

It is an arithmetic number, because the mean of its divisors is an integer number (5298760768).

Almost surely, 2^21100422121 is an apocalyptic number.

It is an amenable number.

21100422121 is a deficient number, since it is larger than the sum of its proper divisors (94620951).

21100422121 is an equidigital number, since it uses as much as digits as its factorization.

21100422121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94620950.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21100422121 its reverse (12122400112), we get a palindrome (33222822233).

The spelling of 21100422121 in words is "twenty-one billion, one hundred million, four hundred twenty-two thousand, one hundred twenty-one".