978678521 has 8 divisors (see below), whose sum is σ = 984774024. Its totient is φ = 972599680.

The previous prime is 978678511. The next prime is 978678553. The reversal of 978678521 is 125876879.

It can be written as a sum of positive squares in 4 ways, for example, as 50623225 + 928055296 = 7115^2 + 30464^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 978678521 - 2¹⁸ = 978416377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (978678511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126011 + ... + 133551.

It is an arithmetic number, because the mean of its divisors is an integer number (123096753).

Almost surely, 2^978678521 is an apocalyptic number.

It is an amenable number.

978678521 is a deficient number, since it is larger than the sum of its proper divisors (6095503).

978678521 is a wasteful number, since it uses less digits than its factorization.

978678521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8331.

The product of its digits is 1693440, while the sum is 53.

The square root of 978678521 is about 31283.8380158190. The cubic root of 978678521 is about 992.8417216501.

The spelling of 978678521 in words is "nine hundred seventy-eight million, six hundred seventy-eight thousand, five hundred twenty-one".