978817 has 4 divisors (see below), whose sum is σ = 1118656. Its totient is φ = 838980.

The previous prime is 978799. The next prime is 978821. The reversal of 978817 is 718879.

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.

It is a cyclic number.

It is not a de Polignac number, because 978817 - 2⁷ = 978689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 978817.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (978017) 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, 69909 + ... + 69922.

It is an arithmetic number, because the mean of its divisors is an integer number (279664).

2⁹⁷⁸⁸¹⁷ is an apocalyptic number.

It is an amenable number.

978817 is a deficient number, since it is larger than the sum of its proper divisors (139839).

978817 is a wasteful number, since it uses less digits than its factorization.

978817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139838.

The product of its digits is 28224, while the sum is 40.

The square root of 978817 is about 989.3518080036. The cubic root of 978817 is about 99.2888547120.

The spelling of 978817 in words is "nine hundred seventy-eight thousand, eight hundred seventeen".