2781537874561 has 2 divisors, whose sum is σ = 2781537874562. Its totient is φ = 2781537874560.

The previous prime is 2781537874559. The next prime is 2781537874571. The reversal of 2781537874561 is 1654787351872.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1726808874561 + 1054729000000 = 1314081^2 + 1027000^2 .

It is a cyclic number.

It is not a de Polignac number, because 2781537874561 - 2¹ = 2781537874559 is a prime.

Together with 2781537874559, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 2781537874493 and 2781537874502.

It is not a weakly prime, because it can be changed into another prime (2781537874571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1390768937280 + 1390768937281.

It is an arithmetic number, because the mean of its divisors is an integer number (1390768937281).

Almost surely, 2^{2781537874561} is an apocalyptic number.

It is an amenable number.

2781537874561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2781537874561 is an equidigital number, since it uses as much as digits as its factorization.

2781537874561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 79027200, while the sum is 64.

The spelling of 2781537874561 in words is "two trillion, seven hundred eighty-one billion, five hundred thirty-seven million, eight hundred seventy-four thousand, five hundred sixty-one".