21158159 has 4 divisors (see below), whose sum is σ = 23081640. Its totient is φ = 19234680.

The previous prime is 21158147. The next prime is 21158161. The reversal of 21158159 is 95185112.

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 21158159 - 2¹⁶ = 21092623 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 (21158119) 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, 961724 + ... + 961745.

It is an arithmetic number, because the mean of its divisors is an integer number (5770410).

Almost surely, 2^21158159 is an apocalyptic number.

21158159 is a deficient number, since it is larger than the sum of its proper divisors (1923481).

21158159 is a wasteful number, since it uses less digits than its factorization.

21158159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1923480.

The product of its digits is 3600, while the sum is 32.

The square root of 21158159 is about 4599.7998869516. The cubic root of 21158159 is about 276.5833030560.

The spelling of 21158159 in words is "twenty-one million, one hundred fifty-eight thousand, one hundred fifty-nine".