18658081 has 4 divisors (see below), whose sum is σ = 20093332. Its totient is φ = 17222832.

The previous prime is 18658069. The next prime is 18658091. The reversal of 18658081 is 18085681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18085681 = 283 ⋅63907.

It can be written as a sum of positive squares in 2 ways, for example, as 1018081 + 17640000 = 1009^2 + 4200^2 .

It is a cyclic number.

It is not a de Polignac number, because 18658081 - 2¹⁷ = 18527009 is a prime.

It is a super-2 number, since 2×18658081² = 696247973205122, which contains 22 as substring.

It is the 4320-th Hogben number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18658081.

It is not an unprimeable number, because it can be changed into a prime (18658091) by changing a digit.

It is a nontrivial repunit in base 4319.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 717606 + ... + 717631.

It is an arithmetic number, because the mean of its divisors is an integer number (5023333).

Almost surely, 2^18658081 is an apocalyptic number.

It is an amenable number.

18658081 is a deficient number, since it is larger than the sum of its proper divisors (1435251).

18658081 is a wasteful number, since it uses less digits than its factorization.

18658081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1435250.

The product of its (nonzero) digits is 15360, while the sum is 37.

The square root of 18658081 is about 4319.5000868156. The cubic root of 18658081 is about 265.2298042194.

The spelling of 18658081 in words is "eighteen million, six hundred fifty-eight thousand, eighty-one".