81237189 has 8 divisors (see below), whose sum is σ = 118163232. Its totient is φ = 49234640.

The previous prime is 81237187. The next prime is 81237223. The reversal of 81237189 is 98173218.

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 81237189 - 2¹ = 81237187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81237187) 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, 1230834 + ... + 1230899.

It is an arithmetic number, because the mean of its divisors is an integer number (14770404).

Almost surely, 2^81237189 is an apocalyptic number.

It is an amenable number.

81237189 is a deficient number, since it is larger than the sum of its proper divisors (36926043).

81237189 is a wasteful number, since it uses less digits than its factorization.

81237189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2461747.

The product of its digits is 24192, while the sum is 39.

The square root of 81237189 is about 9013.1675342246. The cubic root of 81237189 is about 433.0967875987.

The spelling of 81237189 in words is "eighty-one million, two hundred thirty-seven thousand, one hundred eighty-nine".