21891575255089 has 2 divisors, whose sum is σ = 21891575255090. Its totient is φ = 21891575255088.

The previous prime is 21891575255027. The next prime is 21891575255093. The reversal of 21891575255089 is 98055257519812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20228558678689 + 1663016576400 = 4497617^2 + 1289580^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21891575255089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21891575255489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10945787627544 + 10945787627545.

It is an arithmetic number, because the mean of its divisors is an integer number (10945787627545).

Almost surely, 2^{21891575255089} is an apocalyptic number.

It is an amenable number.

21891575255089 is a deficient number, since it is larger than the sum of its proper divisors (1).

21891575255089 is an equidigital number, since it uses as much as digits as its factorization.

21891575255089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720000, while the sum is 67.

The spelling of 21891575255089 in words is "twenty-one trillion, eight hundred ninety-one billion, five hundred seventy-five million, two hundred fifty-five thousand, eighty-nine".