399840841 has 2 divisors, whose sum is σ = 399840842. Its totient is φ = 399840840.

The previous prime is 399840823. The next prime is 399840871. The reversal of 399840841 is 148048993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 398840841 + 1000000 = 19971^2 + 1000^2 .

It is an emirp because it is prime and its reverse (148048993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399840841 - 2¹³ = 399832649 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 399840791 and 399840800.

It is not a weakly prime, because it can be changed into another prime (399840871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199920420 + 199920421.

It is an arithmetic number, because the mean of its divisors is an integer number (199920421).

Almost surely, 2^399840841 is an apocalyptic number.

It is an amenable number.

399840841 is a deficient number, since it is larger than the sum of its proper divisors (1).

399840841 is an equidigital number, since it uses as much as digits as its factorization.

399840841 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 399840841 is about 19996.0206291152. The cubic root of 399840841 is about 736.7085623022.

The spelling of 399840841 in words is "three hundred ninety-nine million, eight hundred forty thousand, eight hundred forty-one".