399320081 has 2 divisors, whose sum is σ = 399320082. Its totient is φ = 399320080.

The previous prime is 399320063. The next prime is 399320087. The reversal of 399320081 is 180023993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 303456400 + 95863681 = 17420^2 + 9791^2 .

It is a cyclic number.

It is not a de Polignac number, because 399320081 - 2¹⁰ = 399319057 is a prime.

It is a super-2 number, since 2×399320081² = 318913054179693122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399320087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199660040 + 199660041.

It is an arithmetic number, because the mean of its divisors is an integer number (199660041).

Almost surely, 2^399320081 is an apocalyptic number.

It is an amenable number.

399320081 is a deficient number, since it is larger than the sum of its proper divisors (1).

399320081 is an equidigital number, since it uses as much as digits as its factorization.

399320081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 399320081 is about 19982.9947955756. The cubic root of 399320081 is about 736.3885891287.

The spelling of 399320081 in words is "three hundred ninety-nine million, three hundred twenty thousand, eighty-one".