981691 has 2 divisors, whose sum is σ = 981692. Its totient is φ = 981690.

The previous prime is 981683. The next prime is 981697. The reversal of 981691 is 196189.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 981691 - 2³ = 981683 is a prime.

It is not a weakly prime, because it can be changed into another prime (981697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490845 + 490846.

It is an arithmetic number, because the mean of its divisors is an integer number (490846).

2⁹⁸¹⁶⁹¹ is an apocalyptic number.

981691 is a deficient number, since it is larger than the sum of its proper divisors (1).

981691 is an equidigital number, since it uses as much as digits as its factorization.

981691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 981691 is about 990.8032095225. The cubic root of 981691 is about 99.3859369844.

The spelling of 981691 in words is "nine hundred eighty-one thousand, six hundred ninety-one".