399183881 has 2 divisors, whose sum is σ = 399183882. Its totient is φ = 399183880.

The previous prime is 399183857. The next prime is 399183907. The reversal of 399183881 is 188381993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 359292025 + 39891856 = 18955^2 + 6316^2 .

It is an emirp because it is prime and its reverse (188381993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399183881 - 2¹⁰ = 399182857 is a prime.

It is a super-2 number, since 2×399183881² = 318695541700444322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399183821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199591940 + 199591941.

It is an arithmetic number, because the mean of its divisors is an integer number (199591941).

Almost surely, 2^399183881 is an apocalyptic number.

It is an amenable number.

399183881 is a deficient number, since it is larger than the sum of its proper divisors (1).

399183881 is an equidigital number, since it uses as much as digits as its factorization.

399183881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 50.

The square root of 399183881 is about 19979.5866073350. The cubic root of 399183881 is about 736.3048571922.

The spelling of 399183881 in words is "three hundred ninety-nine million, one hundred eighty-three thousand, eight hundred eighty-one".