21159385 has 16 divisors (see below), whose sum is σ = 27449856. Its totient is φ = 15565248.

The previous prime is 21159377. The next prime is 21159389. The reversal of 21159385 is 58395112.

It is a cyclic number.

It is not a de Polignac number, because 21159385 - 2³ = 21159377 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21159385.

It is not an unprimeable number, because it can be changed into a prime (21159389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23412 + ... + 24298.

It is an arithmetic number, because the mean of its divisors is an integer number (1715616).

Almost surely, 2^21159385 is an apocalyptic number.

It is an amenable number.

21159385 is a deficient number, since it is larger than the sum of its proper divisors (6290471).

21159385 is a wasteful number, since it uses less digits than its factorization.

21159385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1272.

The product of its digits is 10800, while the sum is 34.

The square root of 21159385 is about 4599.9331516882. The cubic root of 21159385 is about 276.5886451178.

The spelling of 21159385 in words is "twenty-one million, one hundred fifty-nine thousand, three hundred eighty-five".