18816506 has 4 divisors (see below), whose sum is σ = 28224762. Its totient is φ = 9408252.

The previous prime is 18816503. The next prime is 18816533. The reversal of 18816506 is 60561881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60561881 = 53 ⋅1142677.

It can be written as a sum of positive squares in only one way, i.e., 9665881 + 9150625 = 3109^2 + 3025^2 .

It is not an unprimeable number, because it can be changed into a prime (18816503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4704125 + ... + 4704128.

Almost surely, 2^18816506 is an apocalyptic number.

18816506 is a deficient number, since it is larger than the sum of its proper divisors (9408256).

18816506 is an equidigital number, since it uses as much as digits as its factorization.

18816506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9408255.

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 18816506 is about 4337.7996726451. The cubic root of 18816506 is about 265.9783746340.

The spelling of 18816506 in words is "eighteen million, eight hundred sixteen thousand, five hundred six".