18131909 has 8 divisors (see below), whose sum is σ = 19356480. Its totient is φ = 16934400.

The previous prime is 18131879. The next prime is 18131921. The reversal of 18131909 is 90913181.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18131909 is a prime.

It is a super-2 number, since 2×18131909² = 657532247968562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18131209) 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, 5372 + ... + 8069.

It is an arithmetic number, because the mean of its divisors is an integer number (2419560).

Almost surely, 2^18131909 is an apocalyptic number.

18131909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18131909 is a deficient number, since it is larger than the sum of its proper divisors (1224571).

18131909 is a wasteful number, since it uses less digits than its factorization.

18131909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13531.

The product of its (nonzero) digits is 1944, while the sum is 32.

The square root of 18131909 is about 4258.1579350700. The cubic root of 18131909 is about 262.7127659719.

The spelling of 18131909 in words is "eighteen million, one hundred thirty-one thousand, nine hundred nine".