2782778307805 has 4 divisors (see below), whose sum is σ = 3339333969372. Its totient is φ = 2226222646240.

The previous prime is 2782778307763. The next prime is 2782778307817. The reversal of 2782778307805 is 5087038772872.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2006058653316 + 776719654489 = 1416354^2 + 881317^2 .

It is not a de Polignac number, because 2782778307805 - 2¹¹ = 2782778305757 is a prime.

It is a super-2 number, since 2×2782778307805² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 278277830776 + ... + 278277830785.

It is an arithmetic number, because the mean of its divisors is an integer number (834833492343).

Almost surely, 2^{2782778307805} is an apocalyptic number.

It is an amenable number.

2782778307805 is a deficient number, since it is larger than the sum of its proper divisors (556555661567).

2782778307805 is an equidigital number, since it uses as much as digits as its factorization.

2782778307805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556555661566.

The product of its (nonzero) digits is 73758720, while the sum is 64.

The spelling of 2782778307805 in words is "two trillion, seven hundred eighty-two billion, seven hundred seventy-eight million, three hundred seven thousand, eight hundred five".