18661236 has 48 divisors (see below), whose sum is σ = 47974080. Its totient is φ = 5598720.

The previous prime is 18661217. The next prime is 18661243. The reversal of 18661236 is 63216681.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 18661197 and 18661206.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13740 + ... + 15036.

It is an arithmetic number, because the mean of its divisors is an integer number (999460).

Almost surely, 2^18661236 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18661236, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23987040).

18661236 is an abundant number, since it is smaller than the sum of its proper divisors (29312844).

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

18661236 is a wasteful number, since it uses less digits than its factorization.

18661236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424 (or 1422 counting only the distinct ones).

The product of its digits is 10368, while the sum is 33.

The square root of 18661236 is about 4319.8652756770. The cubic root of 18661236 is about 265.2447531107.

The spelling of 18661236 in words is "eighteen million, six hundred sixty-one thousand, two hundred thirty-six".