731981 has 2 divisors, whose sum is σ = 731982. Its totient is φ = 731980.

The previous prime is 731957. The next prime is 731999. The reversal of 731981 is 189137.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 714025 + 17956 = 845^2 + 134^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-731981 is a prime.

It is a super-2 number, since 2×731981² = 1071592368722, which contains 22 as substring.

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 731981.

It is not a weakly prime, because it can be changed into another prime (731911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 365990 + 365991.

It is an arithmetic number, because the mean of its divisors is an integer number (365991).

2⁷³¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

731981 is a deficient number, since it is larger than the sum of its proper divisors (1).

731981 is an equidigital number, since it uses as much as digits as its factorization.

731981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 29.

The square root of 731981 is about 855.5588816674. The cubic root of 731981 is about 90.1225080634.

The spelling of 731981 in words is "seven hundred thirty-one thousand, nine hundred eighty-one".