18221706 has 32 divisors (see below), whose sum is σ = 40826880. Its totient is φ = 6023808.

The previous prime is 18221701. The next prime is 18221711. The reversal of 18221706 is 60712281.

It is an interprime number because it is at equal distance from previous prime (18221701) and next prime (18221711).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 18221706.

It is not an unprimeable number, because it can be changed into a prime (18221701) 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, 5530 + ... + 8186.

It is an arithmetic number, because the mean of its divisors is an integer number (1275840).

Almost surely, 2^18221706 is an apocalyptic number.

18221706 is an abundant number, since it is smaller than the sum of its proper divisors (22605174).

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

18221706 is a wasteful number, since it uses less digits than its factorization.

18221706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2795 (or 2789 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 18221706 is about 4268.6890259188. The cubic root of 18221706 is about 263.1457408099.

Adding to 18221706 its reverse (60712281), we get a palindrome (78933987).

The spelling of 18221706 in words is "eighteen million, two hundred twenty-one thousand, seven hundred six".