18012216 has 16 divisors (see below), whose sum is σ = 45030600. Its totient is φ = 6004064.

The previous prime is 18012199. The next prime is 18012217. The reversal of 18012216 is 61221081.

It is a junction number, because it is equal to n+sod(n) for n = 18012192 and 18012201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18012217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 375231 + ... + 375278.

Almost surely, 2^18012216 is an apocalyptic number.

It is an amenable number.

18012216 is an abundant number, since it is smaller than the sum of its proper divisors (27018384).

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

18012216 is a wasteful number, since it uses less digits than its factorization.

18012216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750518 (or 750514 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 18012216 is about 4244.0801123447. The cubic root of 18012216 is about 262.1334130081.

Adding to 18012216 its reverse (61221081), we get a palindrome (79233297).

The spelling of 18012216 in words is "eighteen million, twelve thousand, two hundred sixteen".