18213689 has 4 divisors (see below), whose sum is σ = 19614756. Its totient is φ = 16812624.

The previous prime is 18213667. The next prime is 18213703. The reversal of 18213689 is 98631281.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2941225 + 15272464 = 1715^2 + 3908^2 .

It is a cyclic number.

It is not a de Polignac number, because 18213689 - 2¹⁶ = 18148153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18213659) 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, 700514 + ... + 700539.

It is an arithmetic number, because the mean of its divisors is an integer number (4903689).

Almost surely, 2^18213689 is an apocalyptic number.

It is an amenable number.

18213689 is a deficient number, since it is larger than the sum of its proper divisors (1401067).

18213689 is a wasteful number, since it uses less digits than its factorization.

18213689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1401066.

The product of its digits is 20736, while the sum is 38.

The square root of 18213689 is about 4267.7498755199. The cubic root of 18213689 is about 263.1071430908.

The spelling of 18213689 in words is "eighteen million, two hundred thirteen thousand, six hundred eighty-nine".