439981 has 2 divisors, whose sum is σ = 439982. Its totient is φ = 439980.

The previous prime is 439973. The next prime is 439991. The reversal of 439981 is 189934.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 401956 + 38025 = 634^2 + 195^2 .

It is a cyclic number.

It is not a de Polignac number, because 439981 - 2³ = 439973 is a prime.

It is a super-2 number, since 2×439981² = 387166560722, which contains 22 as substring.

439981 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (439961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 219990 + 219991.

It is an arithmetic number, because the mean of its divisors is an integer number (219991).

2⁴³⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

439981 is a deficient number, since it is larger than the sum of its proper divisors (1).

439981 is an equidigital number, since it uses as much as digits as its factorization.

439981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 34.

The square root of 439981 is about 663.3106361276. The cubic root of 439981 is about 76.0579544101.

Subtracting from 439981 its reverse (189934), we obtain a cube (250047 = 63³).

The spelling of 439981 in words is "four hundred thirty-nine thousand, nine hundred eighty-one".