816641 has 4 divisors (see below), whose sum is σ = 933312. Its totient is φ = 699972.

The previous prime is 816593. The next prime is 816649. The reversal of 816641 is 146618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 146618 = 2 ⋅73309.

It is a de Polignac number, because none of the positive numbers 2^k-816641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 816641.

It is not an unprimeable number, because it can be changed into a prime (816649) 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, 58325 + ... + 58338.

It is an arithmetic number, because the mean of its divisors is an integer number (233328).

2⁸¹⁶⁶⁴¹ is an apocalyptic number.

It is an amenable number.

816641 is a deficient number, since it is larger than the sum of its proper divisors (116671).

816641 is a wasteful number, since it uses less digits than its factorization.

816641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116670.

The product of its digits is 1152, while the sum is 26.

The square root of 816641 is about 903.6819130645. The cubic root of 816641 is about 93.4710368125.

The spelling of 816641 in words is "eight hundred sixteen thousand, six hundred forty-one".