11971647071 has 4 divisors (see below), whose sum is σ = 12250057512. Its totient is φ = 11693236632.

The previous prime is 11971647047. The next prime is 11971647119. The reversal of 11971647071 is 17074617911.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11971647071 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 (11971647011) 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, 139205156 + ... + 139205241.

It is an arithmetic number, because the mean of its divisors is an integer number (3062514378).

Almost surely, 2^11971647071 is an apocalyptic number.

11971647071 is a deficient number, since it is larger than the sum of its proper divisors (278410441).

11971647071 is an equidigital number, since it uses as much as digits as its factorization.

11971647071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278410440.

The product of its (nonzero) digits is 74088, while the sum is 44.

The spelling of 11971647071 in words is "eleven billion, nine hundred seventy-one million, six hundred forty-seven thousand, seventy-one".