8399921807917 has 2 divisors, whose sum is σ = 8399921807918. Its totient is φ = 8399921807916.

The previous prime is 8399921807897. The next prime is 8399921807933. The reversal of 8399921807917 is 7197081299938.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4895129700036 + 3504792107881 = 2212494^2 + 1872109^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8399921807917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8399921807917.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8399921807947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4199960903958 + 4199960903959.

It is an arithmetic number, because the mean of its divisors is an integer number (4199960903959).

Almost surely, 2^{8399921807917} is an apocalyptic number.

It is an amenable number.

8399921807917 is a deficient number, since it is larger than the sum of its proper divisors (1).

8399921807917 is an equidigital number, since it uses as much as digits as its factorization.

8399921807917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 123451776, while the sum is 73.

The spelling of 8399921807917 in words is "eight trillion, three hundred ninety-nine billion, nine hundred twenty-one million, eight hundred seven thousand, nine hundred seventeen".