21899239 has 4 divisors (see below), whose sum is σ = 21980320. Its totient is φ = 21818160.

The previous prime is 21899219. The next prime is 21899249. The reversal of 21899239 is 93299812.

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 21899239 - 2¹³ = 21891047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21899195 and 21899204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21899219) 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, 40134 + ... + 40675.

It is an arithmetic number, because the mean of its divisors is an integer number (5495080).

Almost surely, 2^21899239 is an apocalyptic number.

21899239 is a deficient number, since it is larger than the sum of its proper divisors (81081).

21899239 is an equidigital number, since it uses as much as digits as its factorization.

21899239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81080.

The product of its digits is 69984, while the sum is 43.

The square root of 21899239 is about 4679.6622741390. The cubic root of 21899239 is about 279.7754960613.

The spelling of 21899239 in words is "twenty-one million, eight hundred ninety-nine thousand, two hundred thirty-nine".