2787991557121 has 2 divisors, whose sum is σ = 2787991557122. Its totient is φ = 2787991557120.

The previous prime is 2787991557119. The next prime is 2787991557149. The reversal of 2787991557121 is 1217551997872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1721511940096 + 1066479617025 = 1312064^2 + 1032705^2 .

It is a cyclic number.

It is not a de Polignac number, because 2787991557121 - 2¹ = 2787991557119 is a prime.

Together with 2787991557119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2787991557101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1393995778560 + 1393995778561.

It is an arithmetic number, because the mean of its divisors is an integer number (1393995778561).

Almost surely, 2^{2787991557121} is an apocalyptic number.

It is an amenable number.

2787991557121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2787991557121 is an equidigital number, since it uses as much as digits as its factorization.

2787991557121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22226400, while the sum is 64.

The spelling of 2787991557121 in words is "two trillion, seven hundred eighty-seven billion, nine hundred ninety-one million, five hundred fifty-seven thousand, one hundred twenty-one".