18218356 has 48 divisors (see below), whose sum is σ = 37403856. Its totient is φ = 7686144.

The previous prime is 18218329. The next prime is 18218357. The reversal of 18218356 is 65381281.

It can be written as a sum of positive squares in 8 ways, for example, as 70756 + 18147600 = 266^2 + 4260^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18218357) 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, 32430 + ... + 32986.

It is an arithmetic number, because the mean of its divisors is an integer number (779247).

Almost surely, 2^18218356 is an apocalyptic number.

It is an amenable number.

18218356 is an abundant number, since it is smaller than the sum of its proper divisors (19185500).

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

18218356 is a wasteful number, since it uses less digits than its factorization.

18218356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628 (or 626 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 18218356 is about 4268.2966157473. The cubic root of 18218356 is about 263.1296136654.

The spelling of 18218356 in words is "eighteen million, two hundred eighteen thousand, three hundred fifty-six".