21102121022111 has 4 divisors (see below), whose sum is σ = 21102252763992. Its totient is φ = 21101989280232.

The previous prime is 21102121022083. The next prime is 21102121022119. The reversal of 21102121022111 is 11122012120112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21102121022111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21102121022111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102121022119) 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, 65630381 + ... + 65951126.

It is an arithmetic number, because the mean of its divisors is an integer number (5275563190998).

Almost surely, 2^{21102121022111} is an apocalyptic number.

21102121022111 is a deficient number, since it is larger than the sum of its proper divisors (131741881).

21102121022111 is a wasteful number, since it uses less digits than its factorization.

21102121022111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131741880.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21102121022111 its reverse (11122012120112), we get a palindrome (32224133142223).

The spelling of 21102121022111 in words is "twenty-one trillion, one hundred two billion, one hundred twenty-one million, twenty-two thousand, one hundred eleven".