20009181 has 8 divisors (see below), whose sum is σ = 26741440. Its totient is φ = 13308192.

The previous prime is 20009173. The next prime is 20009183. The reversal of 20009181 is 18190002.

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

It is not a de Polignac number, because 20009181 - 2³ = 20009173 is a prime.

It is a super-2 number, since 2×20009181² = 800734648581522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20009183) 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, 6280 + ... + 8913.

It is an arithmetic number, because the mean of its divisors is an integer number (3342680).

Almost surely, 2^20009181 is an apocalyptic number.

It is an amenable number.

20009181 is a deficient number, since it is larger than the sum of its proper divisors (6732259).

20009181 is a wasteful number, since it uses less digits than its factorization.

20009181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15635.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 20009181 is about 4473.1623042318. The cubic root of 20009181 is about 271.4832904191.

Adding to 20009181 its reverse (18190002), we get a palindrome (38199183).

The spelling of 20009181 in words is "twenty million, nine thousand, one hundred eighty-one".