26645639857 has 2 divisors, whose sum is σ = 26645639858. Its totient is φ = 26645639856.

The previous prime is 26645639831. The next prime is 26645639897. The reversal of 26645639857 is 75893654662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16977047616 + 9668592241 = 130296^2 + 98329^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26645639857 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 26645639795 and 26645639804.

It is not a weakly prime, because it can be changed into another prime (26645639897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13322819928 + 13322819929.

It is an arithmetic number, because the mean of its divisors is an integer number (13322819929).

Almost surely, 2^26645639857 is an apocalyptic number.

It is an amenable number.

26645639857 is a deficient number, since it is larger than the sum of its proper divisors (1).

26645639857 is an equidigital number, since it uses as much as digits as its factorization.

26645639857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 65318400, while the sum is 61.

The spelling of 26645639857 in words is "twenty-six billion, six hundred forty-five million, six hundred thirty-nine thousand, eight hundred fifty-seven".