21339899 has 4 divisors (see below), whose sum is σ = 24388464. Its totient is φ = 18291336.

The previous prime is 21339889. The next prime is 21339917. The reversal of 21339899 is 99893312.

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

It is not a de Polignac number, because 21339899 - 2²⁴ = 4562683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21339809) 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, 1524272 + ... + 1524285.

It is an arithmetic number, because the mean of its divisors is an integer number (6097116).

Almost surely, 2^21339899 is an apocalyptic number.

21339899 is a deficient number, since it is larger than the sum of its proper divisors (3048565).

21339899 is an equidigital number, since it uses as much as digits as its factorization.

21339899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3048564.

The product of its digits is 104976, while the sum is 44.

The square root of 21339899 is about 4619.5128531048. The cubic root of 21339899 is about 277.3729591907.

The spelling of 21339899 in words is "twenty-one million, three hundred thirty-nine thousand, eight hundred ninety-nine".