778839785361 has 81 divisors (see below), whose sum is σ = 1265654050843. Its totient is φ = 461169128640.

The previous prime is 778839785231. The next prime is 778839785371. The reversal of 778839785361 is 163587938877.

The square root of 778839785361 is 882519.

It is a perfect power (a square), and thus also a powerful number.

778839785361 is a `hidden beast` number, since 7 + 7 + 8 + 83 + 9 + 7 + 8 + 536 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 128365274961 + 650474510400 = 358281^2 + 806520^2 .

It is not a de Polignac number, because 778839785361 - 2²³ = 778831396753 is a prime.

It is a super-2 number, since 2×778839785361² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

Its product of digits (426746880) is a multiple of the sum of its prime divisors (630).

It is a self number, because there is not a number n which added to its sum of digits gives 778839785361.

It is not an unprimeable number, because it can be changed into a prime (778839785371) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1368786685 + ... + 1368787253.

Almost surely, 2^778839785361 is an apocalyptic number.

778839785361 is the 882519-th square number.

778839785361 is the 441260-th centered octagonal number.

It is an amenable number.

778839785361 is a deficient number, since it is larger than the sum of its proper divisors (486814265482).

778839785361 is an equidigital number, since it uses as much as digits as its factorization.

778839785361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260 (or 630 counting only the distinct ones).

The product of its digits is 426746880, while the sum is 72.

The spelling of 778839785361 in words is "seven hundred seventy-eight billion, eight hundred thirty-nine million, seven hundred eighty-five thousand, three hundred sixty-one".