8399921807897 has 2 divisors, whose sum is σ = 8399921807898. Its totient is φ = 8399921807896.

The previous prime is 8399921807869. The next prime is 8399921807917. The reversal of 8399921807897 is 7987081299938.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5769488704576 + 2630433103321 = 2401976^2 + 1621861^2 .

It is a cyclic number.

It is not a de Polignac number, because 8399921807897 - 2²⁸ = 8399653372441 is a prime.

It is not a weakly prime, because it can be changed into another prime (8399921801897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4199960903948 + 4199960903949.

It is an arithmetic number, because the mean of its divisors is an integer number (4199960903949).

Almost surely, 2^{8399921807897} is an apocalyptic number.

It is an amenable number.

8399921807897 is a deficient number, since it is larger than the sum of its proper divisors (1).

8399921807897 is an equidigital number, since it uses as much as digits as its factorization.

8399921807897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 987614208, while the sum is 80.

The spelling of 8399921807897 in words is "eight trillion, three hundred ninety-nine billion, nine hundred twenty-one million, eight hundred seven thousand, eight hundred ninety-seven".