18661099 has 2 divisors, whose sum is σ = 18661100. Its totient is φ = 18661098.

The previous prime is 18661091. The next prime is 18661129. The reversal of 18661099 is 99016681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18661099 - 2³ = 18661091 is a prime.

It is not a weakly prime, because it can be changed into another prime (18661091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9330549 + 9330550.

It is an arithmetic number, because the mean of its divisors is an integer number (9330550).

Almost surely, 2^18661099 is an apocalyptic number.

18661099 is a deficient number, since it is larger than the sum of its proper divisors (1).

18661099 is an equidigital number, since it uses as much as digits as its factorization.

18661099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 18661099 is about 4319.8494186719. The cubic root of 18661099 is about 265.2441040179.

The spelling of 18661099 in words is "eighteen million, six hundred sixty-one thousand, ninety-nine".