18031905 has 24 divisors (see below), whose sum is σ = 31772520. Its totient is φ = 9457920.

The previous prime is 18031903. The next prime is 18031907. The reversal of 18031905 is 50913081.

It is an interprime number because it is at equal distance from previous prime (18031903) and next prime (18031907).

It can be written as a sum of positive squares in 4 ways, for example, as 1115136 + 16916769 = 1056^2 + 4113^2 .

It is not a de Polignac number, because 18031905 - 2¹ = 18031903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18031903) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 540 + ... + 6029.

It is an arithmetic number, because the mean of its divisors is an integer number (1323855).

Almost surely, 2^18031905 is an apocalyptic number.

18031905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18031905 is a deficient number, since it is larger than the sum of its proper divisors (13740615).

18031905 is a wasteful number, since it uses less digits than its factorization.

18031905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6641 (or 6638 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 18031905 is about 4246.3990627354. The cubic root of 18031905 is about 262.2288901623.

Adding to 18031905 its reverse (50913081), we get a palindrome (68944986).

The spelling of 18031905 in words is "eighteen million, thirty-one thousand, nine hundred five".