18609917 has 4 divisors (see below), whose sum is σ = 19704636. Its totient is φ = 17515200.

The previous prime is 18609869. The next prime is 18609919. The reversal of 18609917 is 71990681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71990681 = 7 ⋅10284383.

It can be written as a sum of positive squares in 2 ways, for example, as 15202201 + 3407716 = 3899^2 + 1846^2 .

It is a cyclic number.

It is not a de Polignac number, because 18609917 - 2¹⁸ = 18347773 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 (18609919) 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, 547334 + ... + 547367.

It is an arithmetic number, because the mean of its divisors is an integer number (4926159).

Almost surely, 2^18609917 is an apocalyptic number.

18609917 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18609917 is a deficient number, since it is larger than the sum of its proper divisors (1094719).

18609917 is a wasteful number, since it uses less digits than its factorization.

18609917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1094718.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 18609917 is about 4313.9213020175. The cubic root of 18609917 is about 265.0013860139.

The spelling of 18609917 in words is "eighteen million, six hundred nine thousand, nine hundred seventeen".