18218643 has 8 divisors (see below), whose sum is σ = 24312768. Its totient is φ = 12135144.

The previous prime is 18218639. The next prime is 18218653. The reversal of 18218643 is 34681281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18218643 - 2² = 18218639 is a prime.

It is a super-2 number, since 2×18218643² = 663837905522898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18218653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3180 + ... + 6822.

It is an arithmetic number, because the mean of its divisors is an integer number (3039096).

Almost surely, 2^18218643 is an apocalyptic number.

18218643 is a deficient number, since it is larger than the sum of its proper divisors (6094125).

18218643 is a wasteful number, since it uses less digits than its factorization.

18218643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5313.

The product of its digits is 9216, while the sum is 33.

The square root of 18218643 is about 4268.3302355839. The cubic root of 18218643 is about 263.1309953817.

The spelling of 18218643 in words is "eighteen million, two hundred eighteen thousand, six hundred forty-three".