18720099 has 8 divisors (see below), whose sum is σ = 27733520. Its totient is φ = 12480048.

The previous prime is 18720083. The next prime is 18720173. The reversal of 18720099 is 99002781.

It is a happy number.

It is not a de Polignac number, because 18720099 - 2⁴ = 18720083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18720599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 346642 + ... + 346695.

It is an arithmetic number, because the mean of its divisors is an integer number (3466690).

Almost surely, 2^18720099 is an apocalyptic number.

18720099 is a deficient number, since it is larger than the sum of its proper divisors (9013421).

18720099 is an equidigital number, since it uses as much as digits as its factorization.

18720099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 693346 (or 693340 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 18720099 is about 4326.6729712332. The cubic root of 18720099 is about 265.5233469207.

The spelling of 18720099 in words is "eighteen million, seven hundred twenty thousand, ninety-nine".