21841899 has 4 divisors (see below), whose sum is σ = 29122536. Its totient is φ = 14561264.

The previous prime is 21841891. The next prime is 21841909. The reversal of 21841899 is 99814812.

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 21841899 - 2³ = 21841891 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21841899.

It is not an unprimeable number, because it can be changed into a prime (21841891) 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, 3640314 + ... + 3640319.

It is an arithmetic number, because the mean of its divisors is an integer number (7280634).

Almost surely, 2^21841899 is an apocalyptic number.

21841899 is a deficient number, since it is larger than the sum of its proper divisors (7280637).

21841899 is an equidigital number, since it uses as much as digits as its factorization.

21841899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7280636.

The product of its digits is 41472, while the sum is 42.

The square root of 21841899 is about 4673.5317480467. The cubic root of 21841899 is about 279.5310986973.

The spelling of 21841899 in words is "twenty-one million, eight hundred forty-one thousand, eight hundred ninety-nine".