81358689 has 16 divisors (see below), whose sum is σ = 110627840. Its totient is φ = 53170560.

The previous prime is 81358681. The next prime is 81358721. The reversal of 81358689 is 98685318.

It is not a de Polignac number, because 81358689 - 2³ = 81358681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81358681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74304 + ... + 75390.

It is an arithmetic number, because the mean of its divisors is an integer number (6914240).

Almost surely, 2^81358689 is an apocalyptic number.

It is an amenable number.

81358689 is a deficient number, since it is larger than the sum of its proper divisors (29269151).

81358689 is a wasteful number, since it uses less digits than its factorization.

81358689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1560.

The product of its digits is 414720, while the sum is 48.

The square root of 81358689 is about 9019.9051547120. The cubic root of 81358689 is about 433.3125961806.

The spelling of 81358689 in words is "eighty-one million, three hundred fifty-eight thousand, six hundred eighty-nine".