18161689 has 16 divisors (see below), whose sum is σ = 22570240. Its totient is φ = 14230080.

The previous prime is 18161683. The next prime is 18161707. The reversal of 18161689 is 98616181.

It is a cyclic number.

It is not a de Polignac number, because 18161689 - 2⁵ = 18161657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18161683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9004 + ... + 10834.

It is an arithmetic number, because the mean of its divisors is an integer number (1410640).

Almost surely, 2^18161689 is an apocalyptic number.

It is an amenable number.

18161689 is a deficient number, since it is larger than the sum of its proper divisors (4408551).

18161689 is a wasteful number, since it uses less digits than its factorization.

18161689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960.

The product of its digits is 20736, while the sum is 40.

The square root of 18161689 is about 4261.6533176691. The cubic root of 18161689 is about 262.8565145222.

The spelling of 18161689 in words is "eighteen million, one hundred sixty-one thousand, six hundred eighty-nine".