18180149 has 4 divisors (see below), whose sum is σ = 19578636. Its totient is φ = 16781664.

The previous prime is 18180077. The next prime is 18180161. The reversal of 18180149 is 94108181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1737124 + 16443025 = 1318^2 + 4055^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18180149 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 (18180199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 699224 + ... + 699249.

It is an arithmetic number, because the mean of its divisors is an integer number (4894659).

Almost surely, 2^18180149 is an apocalyptic number.

It is an amenable number.

18180149 is a deficient number, since it is larger than the sum of its proper divisors (1398487).

18180149 is a wasteful number, since it uses less digits than its factorization.

18180149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1398486.

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

The square root of 18180149 is about 4263.8185937021. The cubic root of 18180149 is about 262.9455423686.

The spelling of 18180149 in words is "eighteen million, one hundred eighty thousand, one hundred forty-nine".