18471909 has 4 divisors (see below), whose sum is σ = 24629216. Its totient is φ = 12314604.

The previous prime is 18471889. The next prime is 18471913. The reversal of 18471909 is 90917481.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90917481 = 3 ⋅30305827.

It is not a de Polignac number, because 18471909 - 2¹⁹ = 17947621 is a prime.

It is a super-2 number, since 2×18471909² = 682422844208562, 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 (18471919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3078649 + ... + 3078654.

It is an arithmetic number, because the mean of its divisors is an integer number (6157304).

Almost surely, 2^18471909 is an apocalyptic number.

It is an amenable number.

18471909 is a deficient number, since it is larger than the sum of its proper divisors (6157307).

18471909 is an equidigital number, since it uses as much as digits as its factorization.

18471909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6157306.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 18471909 is about 4297.8958805443. The cubic root of 18471909 is about 264.3446915163.

The spelling of 18471909 in words is "eighteen million, four hundred seventy-one thousand, nine hundred nine".