816999 has 4 divisors (see below), whose sum is σ = 1089336. Its totient is φ = 544664.

The previous prime is 816971. The next prime is 817013. The reversal of 816999 is 999618.

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

It is a cyclic number.

It is not a de Polignac number, because 816999 - 2⁸ = 816743 is a prime.

It is a D-number.

816999 is a modest number, since divided by 999 gives 816 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 816999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136164 + ... + 136169.

It is an arithmetic number, because the mean of its divisors is an integer number (272334).

2⁸¹⁶⁹⁹⁹ is an apocalyptic number.

816999 is a deficient number, since it is larger than the sum of its proper divisors (272337).

816999 is a wasteful number, since it uses less digits than its factorization.

816999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272336.

The product of its digits is 34992, while the sum is 42.

The square root of 816999 is about 903.8799699075. The cubic root of 816999 is about 93.4846934632.

The spelling of 816999 in words is "eight hundred sixteen thousand, nine hundred ninety-nine".