978809761 has 2 divisors, whose sum is σ = 978809762. Its totient is φ = 978809760.

The previous prime is 978809759. The next prime is 978809771. The reversal of 978809761 is 167908879.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 715883536 + 262926225 = 26756^2 + 16215^2 .

It is an emirp because it is prime and its reverse (167908879) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 978809761 - 2¹ = 978809759 is a prime.

Together with 978809759, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (978809771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 489404880 + 489404881.

It is an arithmetic number, because the mean of its divisors is an integer number (489404881).

Almost surely, 2^978809761 is an apocalyptic number.

It is an amenable number.

978809761 is a deficient number, since it is larger than the sum of its proper divisors (1).

978809761 is an equidigital number, since it uses as much as digits as its factorization.

978809761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 55.

The square root of 978809761 is about 31285.9355142211. The cubic root of 978809761 is about 992.8860994244.

The spelling of 978809761 in words is "nine hundred seventy-eight million, eight hundred nine thousand, seven hundred sixty-one".