856042240661 has 2 divisors, whose sum is σ = 856042240662. Its totient is φ = 856042240660.

The previous prime is 856042240633. The next prime is 856042240747. The reversal of 856042240661 is 166042240658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 689481122500 + 166561118161 = 830350^2 + 408119^2 .

It is a cyclic number.

It is not a de Polignac number, because 856042240661 - 2³⁰ = 854968498837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856042290661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428021120330 + 428021120331.

It is an arithmetic number, because the mean of its divisors is an integer number (428021120331).

Almost surely, 2^856042240661 is an apocalyptic number.

It is an amenable number.

856042240661 is a deficient number, since it is larger than the sum of its proper divisors (1).

856042240661 is an equidigital number, since it uses as much as digits as its factorization.

856042240661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 552960, while the sum is 44.

The spelling of 856042240661 in words is "eight hundred fifty-six billion, forty-two million, two hundred forty thousand, six hundred sixty-one".