2156454777779 has 2 divisors, whose sum is σ = 2156454777780. Its totient is φ = 2156454777778.

The previous prime is 2156454777679. The next prime is 2156454777797. The reversal of 2156454777779 is 9777774546512.

Together with next prime (2156454777797) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2156454777779 - 2³² = 2152159810483 is a prime.

It is not a weakly prime, because it can be changed into another prime (2156454777179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078227388889 + 1078227388890.

It is an arithmetic number, because the mean of its divisors is an integer number (1078227388890).

Almost surely, 2^{2156454777779} is an apocalyptic number.

2156454777779 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156454777779 is an equidigital number, since it uses as much as digits as its factorization.

2156454777779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 726062400, while the sum is 71.

The spelling of 2156454777779 in words is "two trillion, one hundred fifty-six billion, four hundred fifty-four million, seven hundred seventy-seven thousand, seven hundred seventy-nine".