581981 has 2 divisors, whose sum is σ = 581982. Its totient is φ = 581980.

The previous prime is 581953. The next prime is 581983. The reversal of 581981 is 189185.

It is a happy number.

581981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 511225 + 70756 = 715^2 + 266^2 .

It is a cyclic number.

It is not a de Polignac number, because 581981 - 2¹⁴ = 565597 is a prime.

It is a super-2 number, since 2×581981² = 677403768722, which contains 22 as substring.

Together with 581983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 581981.

It is not a weakly prime, because it can be changed into another prime (581983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 290990 + 290991.

It is an arithmetic number, because the mean of its divisors is an integer number (290991).

2⁵⁸¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

581981 is a deficient number, since it is larger than the sum of its proper divisors (1).

581981 is an equidigital number, since it uses as much as digits as its factorization.

581981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 32.

The square root of 581981 is about 762.8767921493. The cubic root of 581981 is about 83.4903475283.

The spelling of 581981 in words is "five hundred eighty-one thousand, nine hundred eighty-one".