399899257 has 4 divisors (see below), whose sum is σ = 407444580. Its totient is φ = 392353936.

The previous prime is 399899237. The next prime is 399899261. The reversal of 399899257 is 752998993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 328733161 + 71166096 = 18131^2 + 8436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399899257 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399899195 and 399899204.

It is not an unprimeable number, because it can be changed into a prime (399899237) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3772582 + ... + 3772687.

It is an arithmetic number, because the mean of its divisors is an integer number (101861145).

Almost surely, 2^399899257 is an apocalyptic number.

It is an amenable number.

399899257 is a deficient number, since it is larger than the sum of its proper divisors (7545323).

399899257 is an equidigital number, since it uses as much as digits as its factorization.

399899257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7545322.

The product of its digits is 11022480, while the sum is 61.

The square root of 399899257 is about 19997.4812663995. The cubic root of 399899257 is about 736.7444378034.

The spelling of 399899257 in words is "three hundred ninety-nine million, eight hundred ninety-nine thousand, two hundred fifty-seven".