81030689 has 4 divisors (see below), whose sum is σ = 81176724. Its totient is φ = 80884656.

The previous prime is 81030661. The next prime is 81030701. The reversal of 81030689 is 98603018.

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 10336225 + 70694464 = 3215^2 + 8408^2 .

It is a cyclic number.

It is not a de Polignac number, because 81030689 - 2¹⁶ = 80965153 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81030289) 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, 72182 + ... + 73295.

It is an arithmetic number, because the mean of its divisors is an integer number (20294181).

Almost surely, 2^81030689 is an apocalyptic number.

It is an amenable number.

81030689 is a deficient number, since it is larger than the sum of its proper divisors (146035).

81030689 is a wasteful number, since it uses less digits than its factorization.

81030689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146034.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 81030689 is about 9001.7047829842. The cubic root of 81030689 is about 432.7295076458.

The spelling of 81030689 in words is "eighty-one million, thirty thousand, six hundred eighty-nine".