10991857969 has 2 divisors, whose sum is σ = 10991857970. Its totient is φ = 10991857968.

The previous prime is 10991857967. The next prime is 10991858029. The reversal of 10991857969 is 96975819901.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10959367969 + 32490000 = 104687^2 + 5700^2 .

It is an emirp because it is prime and its reverse (96975819901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 10991857969 - 2¹ = 10991857967 is a prime.

It is a super-2 number, since 2×10991857969² (a number of 21 digits) contains 22 as substring.

Together with 10991857967, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 10991857969.

It is not a weakly prime, because it can be changed into another prime (10991857963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5495928984 + 5495928985.

It is an arithmetic number, because the mean of its divisors is an integer number (5495928985).

Almost surely, 2^10991857969 is an apocalyptic number.

It is an amenable number.

10991857969 is a deficient number, since it is larger than the sum of its proper divisors (1).

10991857969 is an equidigital number, since it uses as much as digits as its factorization.

10991857969 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11022480, while the sum is 64.

The spelling of 10991857969 in words is "ten billion, nine hundred ninety-one million, eight hundred fifty-seven thousand, nine hundred sixty-nine".