18780109 has 4 divisors (see below), whose sum is σ = 18906300. Its totient is φ = 18653920.

The previous prime is 18780103. The next prime is 18780137. The reversal of 18780109 is 90108781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90108781 = 7 ⋅12872683.

It can be written as a sum of positive squares in 2 ways, for example, as 12404484 + 6375625 = 3522^2 + 2525^2 .

It is a cyclic number.

It is not a de Polignac number, because 18780109 - 2⁵ = 18780077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18780103) 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, 62872 + ... + 63169.

It is an arithmetic number, because the mean of its divisors is an integer number (4726575).

Almost surely, 2^18780109 is an apocalyptic number.

It is an amenable number.

18780109 is a deficient number, since it is larger than the sum of its proper divisors (126191).

18780109 is a wasteful number, since it uses less digits than its factorization.

18780109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126190.

The product of its (nonzero) digits is 4032, while the sum is 34.

The square root of 18780109 is about 4333.6023121648. The cubic root of 18780109 is about 265.8067688548.

The spelling of 18780109 in words is "eighteen million, seven hundred eighty thousand, one hundred nine".