23887987991 has 6 divisors (see below), whose sum is σ = 27788067720. Its totient is φ = 20475418236.

The previous prime is 23887987987. The next prime is 23887987999. The reversal of 23887987991 is 19978978832.

It is not a de Polignac number, because 23887987991 - 2² = 23887987987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23887987999) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 243754931 + ... + 243755028.

It is an arithmetic number, because the mean of its divisors is an integer number (4631344620).

Almost surely, 2^23887987991 is an apocalyptic number.

23887987991 is a deficient number, since it is larger than the sum of its proper divisors (3900079729).

23887987991 is an equidigital number, since it uses as much as digits as its factorization.

23887987991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487509973 (or 487509966 counting only the distinct ones).

The product of its digits is 109734912, while the sum is 71.

The spelling of 23887987991 in words is "twenty-three billion, eight hundred eighty-seven million, nine hundred eighty-seven thousand, nine hundred ninety-one".