21102011121 has 4 divisors (see below), whose sum is σ = 28136014832. Its totient is φ = 14068007412.

The previous prime is 21102011113. The next prime is 21102011123. The reversal of 21102011121 is 12111020112.

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 not a de Polignac number, because 21102011121 - 2³ = 21102011113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102011097 and 21102011106.

It is not an unprimeable number, because it can be changed into a prime (21102011123) 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, 3517001851 + ... + 3517001856.

It is an arithmetic number, because the mean of its divisors is an integer number (7034003708).

Almost surely, 2^21102011121 is an apocalyptic number.

It is an amenable number.

21102011121 is a deficient number, since it is larger than the sum of its proper divisors (7034003711).

21102011121 is an equidigital number, since it uses as much as digits as its factorization.

21102011121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7034003710.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21102011121 its reverse (12111020112), we get a palindrome (33213031233).

The spelling of 21102011121 in words is "twenty-one billion, one hundred two million, eleven thousand, one hundred twenty-one".