9965621387 has 2 divisors, whose sum is σ = 9965621388. Its totient is φ = 9965621386.

The previous prime is 9965621377. The next prime is 9965621389. The reversal of 9965621387 is 7831265699.

It is a happy number.

9965621387 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9965621387 - 2²⁶ = 9898512523 is a prime.

Together with 9965621389, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9965621389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4982810693 + 4982810694.

It is an arithmetic number, because the mean of its divisors is an integer number (4982810694).

Almost surely, 2^9965621387 is an apocalyptic number.

9965621387 is a deficient number, since it is larger than the sum of its proper divisors (1).

9965621387 is an equidigital number, since it uses as much as digits as its factorization.

9965621387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4898880, while the sum is 56.

The square root of 9965621387 is about 99827.9589443759. The cubic root of 9965621387 is about 2151.9629728425.

The spelling of 9965621387 in words is "nine billion, nine hundred sixty-five million, six hundred twenty-one thousand, three hundred eighty-seven".