181989019 has 4 divisors (see below), whose sum is σ = 183317544. Its totient is φ = 180660496.

The previous prime is 181989001. The next prime is 181989023. The reversal of 181989019 is 910989181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 181989019 - 2⁵ = 181988987 is a prime.

It is a super-2 number, since 2×181989019² = 66240006073164722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 181989019.

It is not an unprimeable number, because it can be changed into a prime (181989089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 664057 + ... + 664330.

It is an arithmetic number, because the mean of its divisors is an integer number (45829386).

Almost surely, 2^181989019 is an apocalyptic number.

181989019 is a deficient number, since it is larger than the sum of its proper divisors (1328525).

181989019 is a wasteful number, since it uses less digits than its factorization.

181989019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328524.

The product of its (nonzero) digits is 46656, while the sum is 46.

The square root of 181989019 is about 13490.3305741557. The cubic root of 181989019 is about 566.6937131651.

The spelling of 181989019 in words is "one hundred eighty-one million, nine hundred eighty-nine thousand, nineteen".