81133489 has 8 divisors (see below), whose sum is σ = 86950080. Its totient is φ = 75507696.

The previous prime is 81133487. The next prime is 81133501. The reversal of 81133489 is 98433118.

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 81133489 - 2¹ = 81133487 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81133483) 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, 46819 + ... + 48520.

It is an arithmetic number, because the mean of its divisors is an integer number (10868760).

Almost surely, 2^81133489 is an apocalyptic number.

It is an amenable number.

81133489 is a deficient number, since it is larger than the sum of its proper divisors (5816591).

81133489 is a wasteful number, since it uses less digits than its factorization.

81133489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95399.

The product of its digits is 20736, while the sum is 37.

The square root of 81133489 is about 9007.4130026329. The cubic root of 81133489 is about 432.9124251524.

The spelling of 81133489 in words is "eighty-one million, one hundred thirty-three thousand, four hundred eighty-nine".