18681001 has 4 divisors (see below), whose sum is σ = 18692100. Its totient is φ = 18669904.

The previous prime is 18680999. The next prime is 18681029. The reversal of 18681001 is 10018681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12673600 + 6007401 = 3560^2 + 2451^2 .

It is a cyclic number.

It is not a de Polignac number, because 18681001 - 2¹ = 18680999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18681031) 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 3 ways as a sum of consecutive naturals, for example, 2446 + ... + 6583.

It is an arithmetic number, because the mean of its divisors is an integer number (4673025).

Almost surely, 2^18681001 is an apocalyptic number.

It is an amenable number.

18681001 is a deficient number, since it is larger than the sum of its proper divisors (11099).

18681001 is an equidigital number, since it uses as much as digits as its factorization.

18681001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11098.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 18681001 is about 4322.1523573331. The cubic root of 18681001 is about 265.3383645012.

Adding to 18681001 its reverse (10018681), we get a palindrome (28699682).

The spelling of 18681001 in words is "eighteen million, six hundred eighty-one thousand, one".