18461209 has 4 divisors (see below), whose sum is σ = 19881316. Its totient is φ = 17041104.

The previous prime is 18461171. The next prime is 18461227. The reversal of 18461209 is 90216481.

It is a happy number.

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 846400 + 17614809 = 920^2 + 4197^2 .

It is a cyclic number.

It is not a de Polignac number, because 18461209 - 2¹⁵ = 18428441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18461239) 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, 710034 + ... + 710059.

It is an arithmetic number, because the mean of its divisors is an integer number (4970329).

Almost surely, 2^18461209 is an apocalyptic number.

It is an amenable number.

18461209 is a deficient number, since it is larger than the sum of its proper divisors (1420107).

18461209 is a wasteful number, since it uses less digits than its factorization.

18461209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1420106.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 18461209 is about 4296.6509050655. The cubic root of 18461209 is about 264.2936404037.

The spelling of 18461209 in words is "eighteen million, four hundred sixty-one thousand, two hundred nine".