18918436 has 6 divisors (see below), whose sum is σ = 33107270. Its totient is φ = 9459216.

The previous prime is 18918421. The next prime is 18918437. The reversal of 18918436 is 63481981.

It can be written as a sum of positive squares in only one way, i.e., 18662400 + 256036 = 4320^2 + 506^2 .

It is not an unprimeable number, because it can be changed into a prime (18918437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2364801 + ... + 2364808.

Almost surely, 2^18918436 is an apocalyptic number.

It is an amenable number.

18918436 is a deficient number, since it is larger than the sum of its proper divisors (14188834).

18918436 is a wasteful number, since it uses less digits than its factorization.

18918436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4729613 (or 4729611 counting only the distinct ones).

The product of its digits is 41472, while the sum is 40.

The square root of 18918436 is about 4349.5328484792. The cubic root of 18918436 is about 266.4577829490.

The spelling of 18918436 in words is "eighteen million, nine hundred eighteen thousand, four hundred thirty-six".