18506986 has 4 divisors (see below), whose sum is σ = 27760482. Its totient is φ = 9253492.

The previous prime is 18506981. The next prime is 18506987. The reversal of 18506986 is 68960581.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18275625 + 231361 = 4275^2 + 481^2 .

It is not an unprimeable number, because it can be changed into a prime (18506981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4626745 + ... + 4626748.

Almost surely, 2^18506986 is an apocalyptic number.

18506986 is a deficient number, since it is larger than the sum of its proper divisors (9253496).

18506986 is an equidigital number, since it uses as much as digits as its factorization.

18506986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9253495.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 18506986 is about 4301.9746628729. The cubic root of 18506986 is about 264.5119103940.

It can be divided in two parts, 1850 and 6986, that added together give a square (8836 = 94²).

The spelling of 18506986 in words is "eighteen million, five hundred six thousand, nine hundred eighty-six".