18181636 has 48 divisors (see below), whose sum is σ = 37255680. Its totient is φ = 7672320.

The previous prime is 18181633. The next prime is 18181643. The reversal of 18181636 is 63618181.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18181633) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81421 + ... + 81643.

It is an arithmetic number, because the mean of its divisors is an integer number (776160).

Almost surely, 2^18181636 is an apocalyptic number.

It is an amenable number.

18181636 is an abundant number, since it is smaller than the sum of its proper divisors (19074044).

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

18181636 is a wasteful number, since it uses less digits than its factorization.

18181636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364 (or 362 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 18181636 is about 4263.9929643469. The cubic root of 18181636 is about 262.9527111650.

The spelling of 18181636 in words is "eighteen million, one hundred eighty-one thousand, six hundred thirty-six".