816644 has 6 divisors (see below), whose sum is σ = 1429134. Its totient is φ = 408320.

The previous prime is 816593. The next prime is 816649. The reversal of 816644 is 446618.

It can be written as a sum of positive squares in only one way, i.e., 409600 + 407044 = 640^2 + 638^2 .

It is not an unprimeable number, because it can be changed into a prime (816649) by changing a digit.

816644 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102077 + ... + 102084.

It is an arithmetic number, because the mean of its divisors is an integer number (238189).

2⁸¹⁶⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

816644 is a deficient number, since it is larger than the sum of its proper divisors (612490).

816644 is a wasteful number, since it uses less digits than its factorization.

816644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204165 (or 204163 counting only the distinct ones).

The product of its digits is 4608, while the sum is 29.

The square root of 816644 is about 903.6835729391. The cubic root of 816644 is about 93.4711512703.

The spelling of 816644 in words is "eight hundred sixteen thousand, six hundred forty-four".