978905 has 4 divisors (see below), whose sum is σ = 1174692. Its totient is φ = 783120.

The previous prime is 978883. The next prime is 978907. The reversal of 978905 is 509879.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 326041 + 652864 = 571^2 + 808^2 .

It is not a de Polignac number, because 978905 - 2¹⁰ = 977881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (978907) 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, 97886 + ... + 97895.

It is an arithmetic number, because the mean of its divisors is an integer number (293673).

2⁹⁷⁸⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

978905 is a deficient number, since it is larger than the sum of its proper divisors (195787).

978905 is a wasteful number, since it uses less digits than its factorization.

978905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195786.

The product of its (nonzero) digits is 22680, while the sum is 38.

The square root of 978905 is about 989.3962805671. The cubic root of 978905 is about 99.2918301260.

The spelling of 978905 in words is "nine hundred seventy-eight thousand, nine hundred five".