866444154073021 has 2 divisors, whose sum is σ = 866444154073022. Its totient is φ = 866444154073020.

The previous prime is 866444154072997. The next prime is 866444154073051. The reversal of 866444154073021 is 120370451444668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 747897461025796 + 118546693047225 = 27347714^2 + 10887915^2 .

It is a cyclic number.

It is not a de Polignac number, because 866444154073021 - 2⁹ = 866444154072509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866444154073051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433222077036510 + 433222077036511.

It is an arithmetic number, because the mean of its divisors is an integer number (433222077036511).

Almost surely, 2^{866444154073021} is an apocalyptic number.

It is an amenable number.

866444154073021 is a deficient number, since it is larger than the sum of its proper divisors (1).

866444154073021 is an equidigital number, since it uses as much as digits as its factorization.

866444154073021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15482880, while the sum is 55.

The spelling of 866444154073021 in words is "eight hundred sixty-six trillion, four hundred forty-four billion, one hundred fifty-four million, seventy-three thousand, twenty-one".