399232681 has 2 divisors, whose sum is σ = 399232682. Its totient is φ = 399232680.

The previous prime is 399232661. The next prime is 399232721. The reversal of 399232681 is 186232993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 309760000 + 89472681 = 17600^2 + 9459^2 .

It is a cyclic number.

It is not a de Polignac number, because 399232681 - 2⁵ = 399232649 is a prime.

It is a super-2 number, since 2×399232681² = 318773467156895522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399232651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199616340 + 199616341.

It is an arithmetic number, because the mean of its divisors is an integer number (199616341).

Almost surely, 2^399232681 is an apocalyptic number.

It is an amenable number.

399232681 is a deficient number, since it is larger than the sum of its proper divisors (1).

399232681 is an equidigital number, since it uses as much as digits as its factorization.

399232681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 399232681 is about 19980.8078165023. The cubic root of 399232681 is about 736.3348602515.

The spelling of 399232681 in words is "three hundred ninety-nine million, two hundred thirty-two thousand, six hundred eighty-one".