21847438982797 has 2 divisors, whose sum is σ = 21847438982798. Its totient is φ = 21847438982796.

The previous prime is 21847438982711. The next prime is 21847438982893. The reversal of 21847438982797 is 79728983474812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13259895919396 + 8587543063401 = 3641414^2 + 2930451^2 .

It is a cyclic number.

It is not a de Polignac number, because 21847438982797 - 2⁷ = 21847438982669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21847438982497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923719491398 + 10923719491399.

It is an arithmetic number, because the mean of its divisors is an integer number (10923719491399).

Almost surely, 2^{21847438982797} is an apocalyptic number.

It is an amenable number.

21847438982797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21847438982797 is an equidigital number, since it uses as much as digits as its factorization.

21847438982797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2731180032, while the sum is 79.

The spelling of 21847438982797 in words is "twenty-one trillion, eight hundred forty-seven billion, four hundred thirty-eight million, nine hundred eighty-two thousand, seven hundred ninety-seven".