816985 has 8 divisors (see below), whose sum is σ = 1055880. Its totient is φ = 603264.

The previous prime is 816971. The next prime is 817013. The reversal of 816985 is 589618.

It can be written as a sum of positive squares in 4 ways, for example, as 170569 + 646416 = 413^2 + 804^2 .

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 816985 - 2⁷ = 816857 is a prime.

It is an alternating number because its digits alternate between even and odd.

816985 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6220 + ... + 6349.

It is an arithmetic number, because the mean of its divisors is an integer number (131985).

2⁸¹⁶⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

816985 is a deficient number, since it is larger than the sum of its proper divisors (238895).

816985 is a wasteful number, since it uses less digits than its factorization.

816985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12587.

The product of its digits is 17280, while the sum is 37.

The square root of 816985 is about 903.8722254832. The cubic root of 816985 is about 93.4841594792.

The spelling of 816985 in words is "eight hundred sixteen thousand, nine hundred eighty-five".