22181816 has 16 divisors (see below), whose sum is σ = 43780200. Its totient is φ = 10507104.

The previous prime is 22181813. The next prime is 22181879. The reversal of 22181816 is 61818122.

It is a super-2 number, since 2×22181816² = 984065922115712, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22181813) 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, 72815 + ... + 73118.

Almost surely, 2^22181816 is an apocalyptic number.

It is an amenable number.

22181816 is a deficient number, since it is larger than the sum of its proper divisors (21598384).

22181816 is a wasteful number, since it uses less digits than its factorization.

22181816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145958 (or 145954 counting only the distinct ones).

The product of its digits is 1536, while the sum is 29.

The square root of 22181816 is about 4709.7575309139. The cubic root of 22181816 is about 280.9737187462.

Adding to 22181816 its reverse (61818122), we get a palindrome (83999938).

The spelling of 22181816 in words is "twenty-two million, one hundred eighty-one thousand, eight hundred sixteen".