399858917 has 2 divisors, whose sum is σ = 399858918. Its totient is φ = 399858916.

The previous prime is 399858839. The next prime is 399858947. The reversal of 399858917 is 719858993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 240064036 + 159794881 = 15494^2 + 12641^2 .

It is a cyclic number.

It is not a de Polignac number, because 399858917 - 2¹⁰ = 399857893 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399858947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199929458 + 199929459.

It is an arithmetic number, because the mean of its divisors is an integer number (199929459).

Almost surely, 2^399858917 is an apocalyptic number.

It is an amenable number.

399858917 is a deficient number, since it is larger than the sum of its proper divisors (1).

399858917 is an equidigital number, since it uses as much as digits as its factorization.

399858917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4898880, while the sum is 59.

The square root of 399858917 is about 19996.4726139387. The cubic root of 399858917 is about 736.7196638389.

The spelling of 399858917 in words is "three hundred ninety-nine million, eight hundred fifty-eight thousand, nine hundred seventeen".