9995638991 has 4 divisors (see below), whose sum is σ = 10764534312. Its totient is φ = 9226743672.

The previous prime is 9995638987. The next prime is 9995638999. The reversal of 9995638991 is 1998365999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9995638991 - 2² = 9995638987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9995638999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 384447641 + ... + 384447666.

It is an arithmetic number, because the mean of its divisors is an integer number (2691133578).

Almost surely, 2^9995638991 is an apocalyptic number.

9995638991 is a deficient number, since it is larger than the sum of its proper divisors (768895321).

9995638991 is a wasteful number, since it uses less digits than its factorization.

9995638991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768895320.

The product of its digits is 42515280, while the sum is 68.

The square root of 9995638991 is about 99978.1925771816. The cubic root of 9995638991 is about 2154.1214608585.

The spelling of 9995638991 in words is "nine billion, nine hundred ninety-five million, six hundred thirty-eight thousand, nine hundred ninety-one".