2005981 has 2 divisors, whose sum is σ = 2005982. Its totient is φ = 2005980.

The previous prime is 2005957. The next prime is 2006009. The reversal of 2005981 is 1895002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1602756 + 403225 = 1266^2 + 635^2 .

It is a cyclic number.

It is not a de Polignac number, because 2005981 - 2¹⁹ = 1481693 is a prime.

It is a super-2 number, since 2×2005981² = 8047919544722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2005931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1002990 + 1002991.

It is an arithmetic number, because the mean of its divisors is an integer number (1002991).

2^2005981 is an apocalyptic number.

It is an amenable number.

2005981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2005981 is an equidigital number, since it uses as much as digits as its factorization.

2005981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 2005981 is about 1416.3265866318. The cubic root of 2005981 is about 126.1175731316.

The spelling of 2005981 in words is "two million, five thousand, nine hundred eighty-one".