9965655991 has 2 divisors, whose sum is σ = 9965655992. Its totient is φ = 9965655990.

The previous prime is 9965655977. The next prime is 9965656031. The reversal of 9965655991 is 1995565699.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9965655991 - 2¹⁵ = 9965623223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9965655191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4982827995 + 4982827996.

It is an arithmetic number, because the mean of its divisors is an integer number (4982827996).

Almost surely, 2^9965655991 is an apocalyptic number.

9965655991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9965655991 is an equidigital number, since it uses as much as digits as its factorization.

9965655991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29524500, while the sum is 64.

The square root of 9965655991 is about 99828.1322624039. The cubic root of 9965655991 is about 2151.9654636202.

The spelling of 9965655991 in words is "nine billion, nine hundred sixty-five million, six hundred fifty-five thousand, nine hundred ninety-one".