13631818 has 4 divisors (see below), whose sum is σ = 20447730. Its totient is φ = 6815908.

The previous prime is 13631791. The next prime is 13631819. The reversal of 13631818 is 81813631.

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

It can be written as a sum of positive squares in only one way, i.e., 11269449 + 2362369 = 3357^2 + 1537^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 13631818.

It is not an unprimeable number, because it can be changed into a prime (13631819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3407953 + ... + 3407956.

Almost surely, 2^13631818 is an apocalyptic number.

13631818 is a deficient number, since it is larger than the sum of its proper divisors (6815912).

13631818 is an equidigital number, since it uses as much as digits as its factorization.

13631818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6815911.

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

The square root of 13631818 is about 3692.1291960060. The cubic root of 13631818 is about 238.8826416811.

The spelling of 13631818 in words is "thirteen million, six hundred thirty-one thousand, eight hundred eighteen".