18661836 has 12 divisors (see below), whose sum is σ = 43544312. Its totient is φ = 6220608.

The previous prime is 18661831. The next prime is 18661843. The reversal of 18661836 is 63816681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 18661794 and 18661803.

It is not an unprimeable number, because it can be changed into a prime (18661831) 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, 777565 + ... + 777588.

Almost surely, 2^18661836 is an apocalyptic number.

It is an amenable number.

18661836 is an abundant number, since it is smaller than the sum of its proper divisors (24882476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18661836 is a wasteful number, since it uses less digits than its factorization.

18661836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555160 (or 1555158 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 18661836 is about 4319.9347217290. The cubic root of 18661836 is about 265.2475958153.

The spelling of 18661836 in words is "eighteen million, six hundred sixty-one thousand, eight hundred thirty-six".