21922399 has 4 divisors (see below), whose sum is σ = 22018360. Its totient is φ = 21826440.

The previous prime is 21922379. The next prime is 21922423. The reversal of 21922399 is 99322912.

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-21922399 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 (21922319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47637 + ... + 48094.

It is an arithmetic number, because the mean of its divisors is an integer number (5504590).

Almost surely, 2^21922399 is an apocalyptic number.

21922399 is a deficient number, since it is larger than the sum of its proper divisors (95961).

21922399 is an equidigital number, since it uses as much as digits as its factorization.

21922399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95960.

The product of its digits is 17496, while the sum is 37.

The square root of 21922399 is about 4682.1361577810. The cubic root of 21922399 is about 279.8740887965.

The spelling of 21922399 in words is "twenty-one million, nine hundred twenty-two thousand, three hundred ninety-nine".