185400109 has 4 divisors (see below), whose sum is σ = 185853820. Its totient is φ = 184946400.

The previous prime is 185400091. The next prime is 185400151. The reversal of 185400109 is 901004581.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 901004581 = 8543 ⋅105467.

It can be written as a sum of positive squares in 2 ways, for example, as 131744484 + 53655625 = 11478^2 + 7325^2 .

It is a cyclic number.

It is not a de Polignac number, because 185400109 - 2⁹ = 185399597 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 (185400169) 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, 226242 + ... + 227059.

It is an arithmetic number, because the mean of its divisors is an integer number (46463455).

Almost surely, 2^185400109 is an apocalyptic number.

It is an amenable number.

185400109 is a deficient number, since it is larger than the sum of its proper divisors (453711).

185400109 is an equidigital number, since it uses as much as digits as its factorization.

185400109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453710.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 185400109 is about 13616.1708640866. The cubic root of 185400109 is about 570.2124057061.

The spelling of 185400109 in words is "one hundred eighty-five million, four hundred thousand, one hundred nine".