8991323657 has 4 divisors (see below), whose sum is σ = 9210624276. Its totient is φ = 8772023040.

The previous prime is 8991323609. The next prime is 8991323753. The reversal of 8991323657 is 7563231998.

8991323657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2038432201 + 6952891456 = 45149^2 + 83384^2 .

It is a cyclic number.

It is not a de Polignac number, because 8991323657 - 2⁸ = 8991323401 is a prime.

It is a super-2 number, since 2×8991323657² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 8991323599 and 8991323608.

It is not an unprimeable number, because it can be changed into a prime (8991323857) 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 in 3 ways as a sum of consecutive naturals, for example, 109650248 + ... + 109650329.

It is an arithmetic number, because the mean of its divisors is an integer number (2302656069).

Almost surely, 2^8991323657 is an apocalyptic number.

It is an amenable number.

8991323657 is a deficient number, since it is larger than the sum of its proper divisors (219300619).

8991323657 is a wasteful number, since it uses less digits than its factorization.

8991323657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219300618.

The product of its digits is 2449440, while the sum is 53.

The square root of 8991323657 is about 94822.5904360348. The cubic root of 8991323657 is about 2079.4151814473.

The spelling of 8991323657 in words is "eight billion, nine hundred ninety-one million, three hundred twenty-three thousand, six hundred fifty-seven".