18209916 has 36 divisors (see below), whose sum is σ = 46191600. Its totient is φ = 6048768.

The previous prime is 18209909. The next prime is 18209921. The reversal of 18209916 is 61990281.

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12220 + ... + 13628.

It is an arithmetic number, because the mean of its divisors is an integer number (1283100).

Almost surely, 2^18209916 is an apocalyptic number.

It is an amenable number.

18209916 is an abundant number, since it is smaller than the sum of its proper divisors (27981684).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18209916 is a wasteful number, since it uses less digits than its factorization.

18209916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778 (or 1773 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 18209916 is about 4267.3078164107. The cubic root of 18209916 is about 263.0889741226.

The spelling of 18209916 in words is "eighteen million, two hundred nine thousand, nine hundred sixteen".