931981 has 2 divisors, whose sum is σ = 931982. Its totient is φ = 931980.

The previous prime is 931967. The next prime is 931999. The reversal of 931981 is 189139.

931981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 864900 + 67081 = 930^2 + 259^2 .

It is an emirp because it is prime and its reverse (189139) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 931981 - 2⁵ = 931949 is a prime.

It is a super-2 number, since 2×931981² = 1737177168722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (931901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 465990 + 465991.

It is an arithmetic number, because the mean of its divisors is an integer number (465991).

2⁹³¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

931981 is a deficient number, since it is larger than the sum of its proper divisors (1).

931981 is an equidigital number, since it uses as much as digits as its factorization.

931981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 31.

The square root of 931981 is about 965.3916303760. The cubic root of 931981 is about 97.6792582139.

The spelling of 931981 in words is "nine hundred thirty-one thousand, nine hundred eighty-one".