18138356 has 6 divisors (see below), whose sum is σ = 31742130. Its totient is φ = 9069176.

The previous prime is 18138343. The next prime is 18138361. The reversal of 18138356 is 65383181.

It can be written as a sum of positive squares in only one way, i.e., 17926756 + 211600 = 4234^2 + 460^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2267291 + ... + 2267298.

It is an arithmetic number, because the mean of its divisors is an integer number (5290355).

Almost surely, 2^18138356 is an apocalyptic number.

It is an amenable number.

18138356 is a deficient number, since it is larger than the sum of its proper divisors (13603774).

18138356 is a wasteful number, since it uses less digits than its factorization.

18138356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4534593 (or 4534591 counting only the distinct ones).

The product of its digits is 17280, while the sum is 35.

The square root of 18138356 is about 4258.9148852730. The cubic root of 18138356 is about 262.7438990883.

The spelling of 18138356 in words is "eighteen million, one hundred thirty-eight thousand, three hundred fifty-six".