18239985 has 40 divisors (see below), whose sum is σ = 33846120. Its totient is φ = 9386496.

The previous prime is 18239983. The next prime is 18239987. The reversal of 18239985 is 58993281.

It is a happy number.

18239985 is a `hidden beast` number, since 182 + 399 + 85 = 666.

It is an interprime number because it is at equal distance from previous prime (18239983) and next prime (18239987).

It can be written as a sum of positive squares in 4 ways, for example, as 194481 + 18045504 = 441^2 + 4248^2 .

It is not a de Polignac number, because 18239985 - 2¹ = 18239983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 18239985.

It is not an unprimeable number, because it can be changed into a prime (18239983) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 10969 + ... + 12521.

It is an arithmetic number, because the mean of its divisors is an integer number (846153).

Almost surely, 2^18239985 is an apocalyptic number.

18239985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18239985 is a deficient number, since it is larger than the sum of its proper divisors (15606135).

18239985 is a wasteful number, since it uses less digits than its factorization.

18239985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1599 (or 1590 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 18239985 is about 4270.8295447138. The cubic root of 18239985 is about 263.2337024513.

The spelling of 18239985 in words is "eighteen million, two hundred thirty-nine thousand, nine hundred eighty-five".