399967 has 4 divisors (see below), whose sum is σ = 405520. Its totient is φ = 394416.

The previous prime is 399953. The next prime is 399979. The reversal of 399967 is 769993.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399967 is a prime.

It is a Duffinian number.

399967 is a lucky 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 3 ways as a sum of consecutive naturals, for example, 2667 + ... + 2812.

It is an arithmetic number, because the mean of its divisors is an integer number (101380).

2³⁹⁹⁹⁶⁷ is an apocalyptic number.

399967 is a deficient number, since it is larger than the sum of its proper divisors (5553).

399967 is an equidigital number, since it uses as much as digits as its factorization.

399967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5552.

The product of its digits is 91854, while the sum is 43.

The square root of 399967 is about 632.4294427049. The cubic root of 399967 is about 73.6786036998.

It can be divided in two parts, 39996 and 7, that multiplied together give a palindrome (279972).

The spelling of 399967 in words is "three hundred ninety-nine thousand, nine hundred sixty-seven".