18208642 has 4 divisors (see below), whose sum is σ = 27312966. Its totient is φ = 9104320.

The previous prime is 18208621. The next prime is 18208643. The reversal of 18208642 is 24680281.

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., 18071001 + 137641 = 4251^2 + 371^2 .

It is not an unprimeable number, because it can be changed into a prime (18208643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4552159 + ... + 4552162.

Almost surely, 2^18208642 is an apocalyptic number.

18208642 is a deficient number, since it is larger than the sum of its proper divisors (9104324).

18208642 is an equidigital number, since it uses as much as digits as its factorization.

18208642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9104323.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 18208642 is about 4267.1585393561. The cubic root of 18208642 is about 263.0828385796.

The spelling of 18208642 in words is "eighteen million, two hundred eight thousand, six hundred forty-two".