21100122222121 has 4 divisors (see below), whose sum is σ = 21100854716032. Its totient is φ = 21099389728212.

The previous prime is 21100122222077. The next prime is 21100122222139. The reversal of 21100122222121 is 12122222100112.

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 21100122222121 - 2¹⁷ = 21100122091049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100122222521) 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, 366203745 + ... + 366261358.

It is an arithmetic number, because the mean of its divisors is an integer number (5275213679008).

Almost surely, 2^{21100122222121} is an apocalyptic number.

It is an amenable number.

21100122222121 is a deficient number, since it is larger than the sum of its proper divisors (732493911).

21100122222121 is an equidigital number, since it uses as much as digits as its factorization.

21100122222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732493910.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21100122222121 its reverse (12122222100112), we get a palindrome (33222344322233).

The spelling of 21100122222121 in words is "twenty-one trillion, one hundred billion, one hundred twenty-two million, two hundred twenty-two thousand, one hundred twenty-one".