21912159 has 4 divisors (see below), whose sum is σ = 29216216. Its totient is φ = 14608104.

The previous prime is 21912157. The next prime is 21912173. The reversal of 21912159 is 95121912.

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

It is not a de Polignac number, because 21912159 - 2¹ = 21912157 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 (21912157) 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, 3652024 + ... + 3652029.

It is an arithmetic number, because the mean of its divisors is an integer number (7304054).

Almost surely, 2^21912159 is an apocalyptic number.

21912159 is a deficient number, since it is larger than the sum of its proper divisors (7304057).

21912159 is an equidigital number, since it uses as much as digits as its factorization.

21912159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7304056.

The product of its digits is 1620, while the sum is 30.

The square root of 21912159 is about 4681.0425120907. The cubic root of 21912159 is about 279.8305054124.

The spelling of 21912159 in words is "twenty-one million, nine hundred twelve thousand, one hundred fifty-nine".