19980181 has 8 divisors (see below), whose sum is σ = 21821184. Its totient is φ = 18182640.

The previous prime is 19980179. The next prime is 19980187. The reversal of 19980181 is 18108991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19980181 - 2¹ = 19980179 is a prime.

It is a super-2 number, since 2×19980181² = 798415265585522, 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 19980181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19980187) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9901 + ... + 11746.

It is an arithmetic number, because the mean of its divisors is an integer number (2727648).

Almost surely, 2^19980181 is an apocalyptic number.

It is an amenable number.

19980181 is a deficient number, since it is larger than the sum of its proper divisors (1841003).

19980181 is a wasteful number, since it uses less digits than its factorization.

19980181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21731.

The product of its (nonzero) digits is 5184, while the sum is 37.

The square root of 19980181 is about 4469.9195742205. The cubic root of 19980181 is about 271.3520702885.

The spelling of 19980181 in words is "nineteen million, nine hundred eighty thousand, one hundred eighty-one".