780978617 has 2 divisors, whose sum is σ = 780978618. Its totient is φ = 780978616.

The previous prime is 780978607. The next prime is 780978631. The reversal of 780978617 is 716879087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 593945641 + 187032976 = 24371^2 + 13676^2 .

It is a cyclic number.

It is not a de Polignac number, because 780978617 - 2²⁴ = 764201401 is a prime.

It is a super-3 number, since 3×780978617³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (780978607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390489308 + 390489309.

It is an arithmetic number, because the mean of its divisors is an integer number (390489309).

Almost surely, 2^780978617 is an apocalyptic number.

It is an amenable number.

780978617 is a deficient number, since it is larger than the sum of its proper divisors (1).

780978617 is an equidigital number, since it uses as much as digits as its factorization.

780978617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1185408, while the sum is 53.

The square root of 780978617 is about 27945.9946503967. The cubic root of 780978617 is about 920.9012187340.

The spelling of 780978617 in words is "seven hundred eighty million, nine hundred seventy-eight thousand, six hundred seventeen".