11747897991 has 16 divisors (see below), whose sum is σ = 18428076000. Its totient is φ = 7371229824.

The previous prime is 11747897983. The next prime is 11747898007. The reversal of 11747897991 is 19979874711.

11747897991 is a `hidden beast` number, since 1 + 1 + 7 + 478 + 9 + 79 + 91 = 666.

It is not a de Polignac number, because 11747897991 - 2³ = 11747897983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11747897911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12796816 + ... + 12797733.

It is an arithmetic number, because the mean of its divisors is an integer number (1151754750).

Almost surely, 2^11747897991 is an apocalyptic number.

11747897991 is a deficient number, since it is larger than the sum of its proper divisors (6680178009).

11747897991 is a wasteful number, since it uses less digits than its factorization.

11747897991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25594575 (or 25594569 counting only the distinct ones).

The product of its digits is 8001504, while the sum is 63.

The spelling of 11747897991 in words is "eleven billion, seven hundred forty-seven million, eight hundred ninety-seven thousand, nine hundred ninety-one".