21100131121 has 4 divisors (see below), whose sum is σ = 21780780544. Its totient is φ = 20419481700.

The previous prime is 21100131097. The next prime is 21100131127. The reversal of 21100131121 is 12113100112.

It is a happy number.

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 21100131121 - 2¹³ = 21100122929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21100131127) 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, 340324665 + ... + 340324726.

It is an arithmetic number, because the mean of its divisors is an integer number (5445195136).

Almost surely, 2^21100131121 is an apocalyptic number.

It is an amenable number.

21100131121 is a deficient number, since it is larger than the sum of its proper divisors (680649423).

21100131121 is an equidigital number, since it uses as much as digits as its factorization.

21100131121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680649422.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21100131121 its reverse (12113100112), we get a palindrome (33213231233).

The spelling of 21100131121 in words is "twenty-one billion, one hundred million, one hundred thirty-one thousand, one hundred twenty-one".