18908881 has 2 divisors, whose sum is σ = 18908882. Its totient is φ = 18908880.

The previous prime is 18908861. The next prime is 18908891. The reversal of 18908881 is 18880981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17774656 + 1134225 = 4216^2 + 1065^2 .

It is a cyclic number.

It is not a de Polignac number, because 18908881 - 2⁵ = 18908849 is a prime.

It is a super-2 number, since 2×18908881² = 715091561344322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18908801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9454440 + 9454441.

It is an arithmetic number, because the mean of its divisors is an integer number (9454441).

Almost surely, 2^18908881 is an apocalyptic number.

It is an amenable number.

18908881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18908881 is an equidigital number, since it uses as much as digits as its factorization.

18908881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36864, while the sum is 43.

The square root of 18908881 is about 4348.4343159349. The cubic root of 18908881 is about 266.4129160818.

The spelling of 18908881 in words is "eighteen million, nine hundred eight thousand, eight hundred eighty-one".