81041689 has 4 divisors (see below), whose sum is σ = 83836260. Its totient is φ = 78247120.

The previous prime is 81041671. The next prime is 81041711. The reversal of 81041689 is 98614018.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 54878464 + 26163225 = 7408^2 + 5115^2 .

It is a cyclic number.

It is not a de Polignac number, because 81041689 - 2⁷ = 81041561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81041629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1397242 + ... + 1397299.

It is an arithmetic number, because the mean of its divisors is an integer number (20959065).

Almost surely, 2^81041689 is an apocalyptic number.

It is an amenable number.

81041689 is a deficient number, since it is larger than the sum of its proper divisors (2794571).

81041689 is a wasteful number, since it uses less digits than its factorization.

81041689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2794570.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 81041689 is about 9002.3157576259. The cubic root of 81041689 is about 432.7490879195.

The spelling of 81041689 in words is "eighty-one million, forty-one thousand, six hundred eighty-nine".