11531643947 has 4 divisors (see below), whose sum is σ = 11532392640. Its totient is φ = 11530895256.

The previous prime is 11531643943. The next prime is 11531643997. The reversal of 11531643947 is 74934613511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74934613511 = 223 ⋅336029657.

It is a cyclic number.

It is not a de Polignac number, because 11531643947 - 2² = 11531643943 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11531643898 and 11531643907.

It is not an unprimeable number, because it can be changed into a prime (11531643943) 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, 350747 + ... + 382212.

It is an arithmetic number, because the mean of its divisors is an integer number (2883098160).

Almost surely, 2^11531643947 is an apocalyptic number.

11531643947 is a deficient number, since it is larger than the sum of its proper divisors (748693).

11531643947 is an equidigital number, since it uses as much as digits as its factorization.

11531643947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748692.

The product of its digits is 272160, while the sum is 44.

The spelling of 11531643947 in words is "eleven billion, five hundred thirty-one million, six hundred forty-three thousand, nine hundred forty-seven".