21932191 has 4 divisors (see below), whose sum is σ = 21942000. Its totient is φ = 21922384.

The previous prime is 21932173. The next prime is 21932201. The reversal of 21932191 is 19123912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21932191 - 2⁷ = 21932063 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 (21932161) 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, 270 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (5485500).

Almost surely, 2^21932191 is an apocalyptic number.

21932191 is a deficient number, since it is larger than the sum of its proper divisors (9809).

21932191 is an equidigital number, since it uses as much as digits as its factorization.

21932191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9808.

The product of its digits is 972, while the sum is 28.

The square root of 21932191 is about 4683.1817175933. The cubic root of 21932191 is about 279.9157527152.

The spelling of 21932191 in words is "twenty-one million, nine hundred thirty-two thousand, one hundred ninety-one".