21859159 has 4 divisors (see below), whose sum is σ = 24981904. Its totient is φ = 18736416.

The previous prime is 21859157. The next prime is 21859163. The reversal of 21859159 is 95195812.

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 21859159 - 2¹ = 21859157 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 (21859153) 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, 1561362 + ... + 1561375.

It is an arithmetic number, because the mean of its divisors is an integer number (6245476).

Almost surely, 2^21859159 is an apocalyptic number.

21859159 is a deficient number, since it is larger than the sum of its proper divisors (3122745).

21859159 is an equidigital number, since it uses as much as digits as its factorization.

21859159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3122744.

The product of its digits is 32400, while the sum is 40.

The square root of 21859159 is about 4675.3779526366. The cubic root of 21859159 is about 279.6047100693.

The spelling of 21859159 in words is "twenty-one million, eight hundred fifty-nine thousand, one hundred fifty-nine".