399797 has 4 divisors (see below), whose sum is σ = 401196. Its totient is φ = 398400.

The previous prime is 399793. The next prime is 399851. The reversal of 399797 is 797993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 376996 + 22801 = 614^2 + 151^2 .

It is a cyclic number.

It is not a de Polignac number, because 399797 - 2² = 399793 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399793) 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, 98 + ... + 899.

It is an arithmetic number, because the mean of its divisors is an integer number (100299).

2³⁹⁹⁷⁹⁷ is an apocalyptic number.

It is an amenable number.

399797 is a deficient number, since it is larger than the sum of its proper divisors (1399).

399797 is an equidigital number, since it uses as much as digits as its factorization.

399797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1398.

The product of its digits is 107163, while the sum is 44.

The square root of 399797 is about 632.2950260756. The cubic root of 399797 is about 73.6681635571.

It can be divided in two parts, 399 and 797, that multiplied together give a triangular number (318003 = T₇₉₇).

The spelling of 399797 in words is "three hundred ninety-nine thousand, seven hundred ninety-seven".