26220644890021 has 2 divisors, whose sum is σ = 26220644890022. Its totient is φ = 26220644890020.

The previous prime is 26220644890019. The next prime is 26220644890043. The reversal of 26220644890021 is 12009844602262.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15943138608996 + 10277506281025 = 3992886^2 + 3205855^2 .

It is a cyclic number.

It is not a de Polignac number, because 26220644890021 - 2¹ = 26220644890019 is a prime.

Together with 26220644890019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26220644890621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13110322445010 + 13110322445011.

It is an arithmetic number, because the mean of its divisors is an integer number (13110322445011).

Almost surely, 2^{26220644890021} is an apocalyptic number.

It is an amenable number.

26220644890021 is a deficient number, since it is larger than the sum of its proper divisors (1).

26220644890021 is an equidigital number, since it uses as much as digits as its factorization.

26220644890021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 663552, while the sum is 46.

The spelling of 26220644890021 in words is "twenty-six trillion, two hundred twenty billion, six hundred forty-four million, eight hundred ninety thousand, twenty-one".