18491589 has 12 divisors (see below), whose sum is σ = 27631500. Its totient is φ = 11902464.

The previous prime is 18491573. The next prime is 18491621. The reversal of 18491589 is 98519481.

It can be written as a sum of positive squares in 2 ways, for example, as 12659364 + 5832225 = 3558^2 + 2415^2 .

It is not a de Polignac number, because 18491589 - 2⁴ = 18491573 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18491509) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35164 + ... + 35685.

It is an arithmetic number, because the mean of its divisors is an integer number (2302625).

Almost surely, 2^18491589 is an apocalyptic number.

It is an amenable number.

18491589 is a deficient number, since it is larger than the sum of its proper divisors (9139911).

18491589 is a wasteful number, since it uses less digits than its factorization.

18491589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70884 (or 70881 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 18491589 is about 4300.1847634724. The cubic root of 18491589 is about 264.4385359425.

The spelling of 18491589 in words is "eighteen million, four hundred ninety-one thousand, five hundred eighty-nine".