2778456161 has 12 divisors (see below), whose sum is σ = 3027816252. Its totient is φ = 2548368576.

The previous prime is 2778456103. The next prime is 2778456173. The reversal of 2778456161 is 1616548772.

It can be written as a sum of positive squares in 6 ways, for example, as 1283860561 + 1494595600 = 35831^2 + 38660^2 .

It is not a de Polignac number, because 2778456161 - 2²⁶ = 2711347297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2778456101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25826 + ... + 78891.

It is an arithmetic number, because the mean of its divisors is an integer number (252318021).

Almost surely, 2^2778456161 is an apocalyptic number.

It is an amenable number.

2778456161 is a deficient number, since it is larger than the sum of its proper divisors (249360091).

2778456161 is a wasteful number, since it uses less digits than its factorization.

2778456161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104900 (or 104887 counting only the distinct ones).

The product of its digits is 564480, while the sum is 47.

The square root of 2778456161 is about 52711.0629849181. The cubic root of 2778456161 is about 1405.8355336357.

The spelling of 2778456161 in words is "two billion, seven hundred seventy-eight million, four hundred fifty-six thousand, one hundred sixty-one".