81011593 has 4 divisors (see below), whose sum is σ = 87243268. Its totient is φ = 74779920.

The previous prime is 81011561. The next prime is 81011617. The reversal of 81011593 is 39511018.

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 31843449 + 49168144 = 5643^2 + 7012^2 .

It is a cyclic number.

It is not a de Polignac number, because 81011593 - 2⁵ = 81011561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81012593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3115818 + ... + 3115843.

It is an arithmetic number, because the mean of its divisors is an integer number (21810817).

Almost surely, 2^81011593 is an apocalyptic number.

It is an amenable number.

81011593 is a deficient number, since it is larger than the sum of its proper divisors (6231675).

81011593 is a wasteful number, since it uses less digits than its factorization.

81011593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6231674.

The product of its (nonzero) digits is 1080, while the sum is 28.

The square root of 81011593 is about 9000.6440325123. The cubic root of 81011593 is about 432.6955120819.

It can be divided in two parts, 810 and 11593, that added together give a triangular number (12403 = T₁₅₇).

The spelling of 81011593 in words is "eighty-one million, eleven thousand, five hundred ninety-three".