581681321 has 8 divisors (see below), whose sum is σ = 632629704. Its totient is φ = 531619200.

The previous prime is 581681291. The next prime is 581681323. The reversal of 581681321 is 123186185.

It can be written as a sum of positive squares in 4 ways, for example, as 121793296 + 459888025 = 11036^2 + 21445^2 .

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 581681321 - 2¹⁸ = 581419177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (581681323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 220196 + ... + 222821.

It is an arithmetic number, because the mean of its divisors is an integer number (79078713).

Almost surely, 2^581681321 is an apocalyptic number.

It is an amenable number.

581681321 is a deficient number, since it is larger than the sum of its proper divisors (50948383).

581681321 is a wasteful number, since it uses less digits than its factorization.

581681321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443131.

The product of its digits is 11520, while the sum is 35.

The square root of 581681321 is about 24118.0704244763. The cubic root of 581681321 is about 834.7601452905.

The spelling of 581681321 in words is "five hundred eighty-one million, six hundred eighty-one thousand, three hundred twenty-one".