18409181 has 8 divisors (see below), whose sum is σ = 22276800. Its totient is φ = 14851008.

The previous prime is 18409163. The next prime is 18409199. The reversal of 18409181 is 18190481.

It is an interprime number because it is at equal distance from previous prime (18409163) and next prime (18409199).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18409181 - 2¹⁰ = 18408157 is a prime.

It is a super-2 number, since 2×18409181² = 677795890181522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18409481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77231 + ... + 77468.

It is an arithmetic number, because the mean of its divisors is an integer number (2784600).

Almost surely, 2^18409181 is an apocalyptic number.

It is an amenable number.

18409181 is a deficient number, since it is larger than the sum of its proper divisors (3867619).

18409181 is a wasteful number, since it uses less digits than its factorization.

18409181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154723.

The product of its (nonzero) digits is 2304, while the sum is 32.

The square root of 18409181 is about 4290.5921502748. The cubic root of 18409181 is about 264.0451263922.

The spelling of 18409181 in words is "eighteen million, four hundred nine thousand, one hundred eighty-one".