2780663861 has 2 divisors, whose sum is σ = 2780663862. Its totient is φ = 2780663860.

The previous prime is 2780663797. The next prime is 2780663863. The reversal of 2780663861 is 1683660872.

2780663861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2706600625 + 74063236 = 52025^2 + 8606^2 .

It is a cyclic number.

It is not a de Polignac number, because 2780663861 - 2⁶ = 2780663797 is a prime.

Together with 2780663863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2780663863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1390331930 + 1390331931.

It is an arithmetic number, because the mean of its divisors is an integer number (1390331931).

Almost surely, 2^2780663861 is an apocalyptic number.

It is an amenable number.

2780663861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2780663861 is an equidigital number, since it uses as much as digits as its factorization.

2780663861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 47.

The square root of 2780663861 is about 52732.0003508306. Note that the first 3 decimals coincide. The cubic root of 2780663861 is about 1406.2077836979.

The spelling of 2780663861 in words is "two billion, seven hundred eighty million, six hundred sixty-three thousand, eight hundred sixty-one".