439973981 has 2 divisors, whose sum is σ = 439973982. Its totient is φ = 439973980.

The previous prime is 439973959. The next prime is 439973983. The reversal of 439973981 is 189379934.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 248566756 + 191407225 = 15766^2 + 13835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-439973981 is a prime.

It is a super-2 number, since 2×439973981² = 387154207913976722, which contains 22 as substring.

Together with 439973983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (439973983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 219986990 + 219986991.

It is an arithmetic number, because the mean of its divisors is an integer number (219986991).

Almost surely, 2^439973981 is an apocalyptic number.

It is an amenable number.

439973981 is a deficient number, since it is larger than the sum of its proper divisors (1).

439973981 is an equidigital number, since it uses as much as digits as its factorization.

439973981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 53.

The square root of 439973981 is about 20975.5567506562. The cubic root of 439973981 is about 760.5754995810.

The spelling of 439973981 in words is "four hundred thirty-nine million, nine hundred seventy-three thousand, nine hundred eighty-one".