21992111 has 4 divisors (see below), whose sum is σ = 22016424. Its totient is φ = 21967800.

The previous prime is 21992083. The next prime is 21992129. The reversal of 21992111 is 11129912.

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 21992111 - 2¹⁴ = 21975727 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 (21992161) 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, 10745 + ... + 12626.

It is an arithmetic number, because the mean of its divisors is an integer number (5504106).

Almost surely, 2^21992111 is an apocalyptic number.

21992111 is a deficient number, since it is larger than the sum of its proper divisors (24313).

21992111 is an equidigital number, since it uses as much as digits as its factorization.

21992111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24312.

The product of its digits is 324, while the sum is 26.

The square root of 21992111 is about 4689.5747141932. The cubic root of 21992111 is about 280.1704362003.

The spelling of 21992111 in words is "twenty-one million, nine hundred ninety-two thousand, one hundred eleven".