778856461 has 2 divisors, whose sum is σ = 778856462. Its totient is φ = 778856460.

The previous prime is 778856453. The next prime is 778856467. The reversal of 778856461 is 164658877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 763693225 + 15163236 = 27635^2 + 3894^2 .

It is an emirp because it is prime and its reverse (164658877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 778856461 - 2³ = 778856453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 778856399 and 778856408.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (778856467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 389428230 + 389428231.

It is an arithmetic number, because the mean of its divisors is an integer number (389428231).

Almost surely, 2^778856461 is an apocalyptic number.

It is an amenable number.

778856461 is a deficient number, since it is larger than the sum of its proper divisors (1).

778856461 is an equidigital number, since it uses as much as digits as its factorization.

778856461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2257920, while the sum is 52.

The square root of 778856461 is about 27907.9999462520. Note that the first 4 decimals coincide. The cubic root of 778856461 is about 920.0663393404.

The spelling of 778856461 in words is "seven hundred seventy-eight million, eight hundred fifty-six thousand, four hundred sixty-one".