18708409 has 2 divisors, whose sum is σ = 18708410. Its totient is φ = 18708408.

The previous prime is 18708379. The next prime is 18708419. The reversal of 18708409 is 90480781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13162384 + 5546025 = 3628^2 + 2355^2 .

It is a cyclic number.

It is not a de Polignac number, because 18708409 - 2⁵ = 18708377 is a prime.

It is a super-2 number, since 2×18708409² = 700009134622562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18708419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9354204 + 9354205.

It is an arithmetic number, because the mean of its divisors is an integer number (9354205).

Almost surely, 2^18708409 is an apocalyptic number.

It is an amenable number.

18708409 is a deficient number, since it is larger than the sum of its proper divisors (1).

18708409 is an equidigital number, since it uses as much as digits as its factorization.

18708409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 18708409 is about 4325.3218377365. The cubic root of 18708409 is about 265.4680656202.

The spelling of 18708409 in words is "eighteen million, seven hundred eight thousand, four hundred nine".