839981 has 2 divisors, whose sum is σ = 839982.
Its totient is φ = 839980.
The previous prime is 839963. The next prime is 839999. The reversal of 839981 is 189938.
839981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a balanced prime because it is at equal distance from previous prime (839963) and next prime (839999).
It can be written as a sum of positive squares in only one way, i.e., 828100 + 11881 = 910^2 + 109^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-839981 is a prime.
It is a super-2 number, since 2×8399812 = 1411136160722, which contains 22 as substring.
It is a Sophie Germain prime.
It is a Curzon number.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (839911) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 419990 + 419991.
It is an arithmetic number, because the mean of its divisors is an integer number (419991).
2839981 is an apocalyptic number.
It is an amenable number.
839981 is a deficient number, since it is larger than the sum of its proper divisors (1).
839981 is an equidigital number, since it uses as much as digits as its factorization.
839981 is an evil number, because the sum of its binary digits is even.
The product of its digits is 15552, while the sum is 38.
The square root of 839981 is about 916.5047735828.
The cubic root of 839981 is about 94.3531682027.
The spelling of 839981 in words is "eight hundred thirty-nine thousand, nine hundred eighty-one".