817961 has 4 divisors (see below), whose sum is σ = 819924. Its totient is φ = 816000.

The previous prime is 817951. The next prime is 817979. The reversal of 817961 is 169718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 169718 = 2 ⋅84859.

It can be written as a sum of positive squares in 2 ways, for example, as 414736 + 403225 = 644^2 + 635^2 .

It is a cyclic number.

It is not a de Polignac number, because 817961 - 2⁶ = 817897 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 817961.

It is not an unprimeable number, because it can be changed into a prime (817951) 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, 80 + ... + 1281.

It is an arithmetic number, because the mean of its divisors is an integer number (204981).

2⁸¹⁷⁹⁶¹ is an apocalyptic number.

It is an amenable number.

817961 is a deficient number, since it is larger than the sum of its proper divisors (1963).

817961 is a wasteful number, since it uses less digits than its factorization.

817961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1962.

The product of its digits is 3024, while the sum is 32.

The square root of 817961 is about 904.4119636537. The cubic root of 817961 is about 93.5213711908.

The spelling of 817961 in words is "eight hundred seventeen thousand, nine hundred sixty-one".