18166538 has 8 divisors (see below), whose sum is σ = 29345988. Its totient is φ = 8384544.

The previous prime is 18166537. The next prime is 18166541. The reversal of 18166538 is 83566181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17952169 + 214369 = 4237^2 + 463^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (18166537) 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, 349331 + ... + 349382.

Almost surely, 2^18166538 is an apocalyptic number.

18166538 is a deficient number, since it is larger than the sum of its proper divisors (11179450).

18166538 is a wasteful number, since it uses less digits than its factorization.

18166538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 698728.

The product of its digits is 34560, while the sum is 38.

The square root of 18166538 is about 4262.2221903603. Note that the first 3 decimals coincide. The cubic root of 18166538 is about 262.8799058456.

The spelling of 18166538 in words is "eighteen million, one hundred sixty-six thousand, five hundred thirty-eight".