9901897997 has 2 divisors, whose sum is σ = 9901897998. Its totient is φ = 9901897996.

The previous prime is 9901897991. The next prime is 9901898029. The reversal of 9901897997 is 7997981099.

9901897997 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9506445001 + 395452996 = 97501^2 + 19886^2 .

It is a cyclic number.

It is not a de Polignac number, because 9901897997 - 2⁴ = 9901897981 is a prime.

It is a super-2 number, since 2×9901897997² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9901897991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4950948998 + 4950948999.

It is an arithmetic number, because the mean of its divisors is an integer number (4950948999).

Almost surely, 2^9901897997 is an apocalyptic number.

It is an amenable number.

9901897997 is a deficient number, since it is larger than the sum of its proper divisors (1).

9901897997 is an equidigital number, since it uses as much as digits as its factorization.

9901897997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23147208, while the sum is 68.

The square root of 9901897997 is about 99508.2810473581. The cubic root of 9901897997 is about 2147.3663802683.

The spelling of 9901897997 in words is "nine billion, nine hundred one million, eight hundred ninety-seven thousand, nine hundred ninety-seven".