18503890 has 16 divisors (see below), whose sum is σ = 33936408. Its totient is φ = 7261696.

The previous prime is 18503873. The next prime is 18503897. The reversal of 18503890 is 9830581.

It can be written as a sum of positive squares in 4 ways, for example, as 16232841 + 2271049 = 4029^2 + 1507^2 .

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18503897) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 16927 + ... + 17986.

Almost surely, 2^18503890 is an apocalyptic number.

18503890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18503890 is a deficient number, since it is larger than the sum of its proper divisors (15432518).

18503890 is a wasteful number, since it uses less digits than its factorization.

18503890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34973.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 18503890 is about 4301.6148130673. The cubic root of 18503890 is about 264.4971596661.

The spelling of 18503890 in words is "eighteen million, five hundred three thousand, eight hundred ninety".