21247266344797 has 2 divisors, whose sum is σ = 21247266344798. Its totient is φ = 21247266344796.

The previous prime is 21247266344789. The next prime is 21247266344803. The reversal of 21247266344797 is 79744366274212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20315473838361 + 931792506436 = 4507269^2 + 965294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21247266344797 - 2³ = 21247266344789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21247266344747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10623633172398 + 10623633172399.

It is an arithmetic number, because the mean of its divisors is an integer number (10623633172399).

Almost surely, 2^{21247266344797} is an apocalyptic number.

It is an amenable number.

21247266344797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21247266344797 is an equidigital number, since it uses as much as digits as its factorization.

21247266344797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 170698752, while the sum is 64.

The spelling of 21247266344797 in words is "twenty-one trillion, two hundred forty-seven billion, two hundred sixty-six million, three hundred forty-four thousand, seven hundred ninety-seven".