81300581 has 8 divisors (see below), whose sum is σ = 85536024. Its totient is φ = 77172480.

The previous prime is 81300533. The next prime is 81300623. The reversal of 81300581 is 18500318.

It can be written as a sum of positive squares in 4 ways, for example, as 7924225 + 73376356 = 2815^2 + 8566^2 .

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 81300581 - 2⁶ = 81300517 is a prime.

It is a super-2 number, since 2×81300581² = 13219568941875122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81300581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81300181) 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, 25280 + ... + 28313.

It is an arithmetic number, because the mean of its divisors is an integer number (10692003).

Almost surely, 2^81300581 is an apocalyptic number.

It is an amenable number.

81300581 is a deficient number, since it is larger than the sum of its proper divisors (4235443).

81300581 is a wasteful number, since it uses less digits than its factorization.

81300581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53671.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 81300581 is about 9016.6834811920. The cubic root of 81300581 is about 433.2094114420.

Adding to 81300581 its reverse (18500318), we get a palindrome (99800899).

The spelling of 81300581 in words is "eighty-one million, three hundred thousand, five hundred eighty-one".