399997 has 8 divisors (see below), whose sum is σ = 446040. Its totient is φ = 356160.

The previous prime is 399989. The next prime is 400009. The reversal of 399997 is 799993.

It can be written as a sum of positive squares in 4 ways, for example, as 32761 + 367236 = 181^2 + 606^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399997 - 2³ = 399989 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 (399937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154 + ... + 907.

It is an arithmetic number, because the mean of its divisors is an integer number (55755).

2³⁹⁹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

399997 is a deficient number, since it is larger than the sum of its proper divisors (46043).

399997 is a wasteful number, since it uses less digits than its factorization.

399997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1103.

The product of its digits is 137781, while the sum is 46.

The square root of 399997 is about 632.4531603210. The cubic root of 399997 is about 73.6804457708.

It can be divided in two parts, 3999 and 97, that added together give a 12-th power (4096 = 2¹²).

The spelling of 399997 in words is "three hundred ninety-nine thousand, nine hundred ninety-seven".