7980779561 has 2 divisors, whose sum is σ = 7980779562. Its totient is φ = 7980779560.

The previous prime is 7980779507. The next prime is 7980779563. The reversal of 7980779561 is 1659770897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7837737961 + 143041600 = 88531^2 + 11960^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7980779561 is a prime.

Together with 7980779563, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 7980779561.

It is not a weakly prime, because it can be changed into another prime (7980779563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3990389780 + 3990389781.

It is an arithmetic number, because the mean of its divisors is an integer number (3990389781).

Almost surely, 2^7980779561 is an apocalyptic number.

It is an amenable number.

7980779561 is a deficient number, since it is larger than the sum of its proper divisors (1).

7980779561 is an equidigital number, since it uses as much as digits as its factorization.

7980779561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6667920, while the sum is 59.

The square root of 7980779561 is about 89335.2089660062. The cubic root of 7980779561 is about 1998.3970123085.

The spelling of 7980779561 in words is "seven billion, nine hundred eighty million, seven hundred seventy-nine thousand, five hundred sixty-one".