21202112111 has 4 divisors (see below), whose sum is σ = 21202700400. Its totient is φ = 21201523824.

The previous prime is 21202112101. The next prime is 21202112153. The reversal of 21202112111 is 11121120212.

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

It is a cyclic number.

It is not a de Polignac number, because 21202112111 - 2¹⁸ = 21201849967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202112101) 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, 236291 + ... + 313428.

It is an arithmetic number, because the mean of its divisors is an integer number (5300675100).

Almost surely, 2^21202112111 is an apocalyptic number.

21202112111 is a deficient number, since it is larger than the sum of its proper divisors (588289).

21202112111 is an equidigital number, since it uses as much as digits as its factorization.

21202112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588288.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21202112111 its reverse (11121120212), we get a palindrome (32323232323).

The spelling of 21202112111 in words is "twenty-one billion, two hundred two million, one hundred twelve thousand, one hundred eleven".