978765409 has 4 divisors (see below), whose sum is σ = 979900416. Its totient is φ = 977630404.

The previous prime is 978765379. The next prime is 978765419. The reversal of 978765409 is 904567879.

978765409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 978765409 - 2¹⁵ = 978732641 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 978765409.

It is not an unprimeable number, because it can be changed into a prime (978765419) 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, 566209 + ... + 567934.

It is an arithmetic number, because the mean of its divisors is an integer number (244975104).

Almost surely, 2^978765409 is an apocalyptic number.

It is an amenable number.

978765409 is a deficient number, since it is larger than the sum of its proper divisors (1135007).

978765409 is a wasteful number, since it uses less digits than its factorization.

978765409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1135006.

The product of its (nonzero) digits is 3810240, while the sum is 55.

The square root of 978765409 is about 31285.2266892858. The cubic root of 978765409 is about 992.8711025880.

It can be divided in two parts, 97876 and 5409, that added together give a triangular number (103285 = T₄₅₄).

The spelling of 978765409 in words is "nine hundred seventy-eight million, seven hundred sixty-five thousand, four hundred nine".