15891397487 has 4 divisors (see below), whose sum is σ = 18161597136. Its totient is φ = 13621197840.

The previous prime is 15891397477. The next prime is 15891397499. The reversal of 15891397487 is 78479319851.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 15891397487 - 2²⁰ = 15890348911 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 (15891397477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1135099814 + ... + 1135099827.

It is an arithmetic number, because the mean of its divisors is an integer number (4540399284).

Almost surely, 2^15891397487 is an apocalyptic number.

15891397487 is a deficient number, since it is larger than the sum of its proper divisors (2270199649).

15891397487 is an equidigital number, since it uses as much as digits as its factorization.

15891397487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2270199648.

The product of its digits is 15240960, while the sum is 62.

The spelling of 15891397487 in words is "fifteen billion, eight hundred ninety-one million, three hundred ninety-seven thousand, four hundred eighty-seven".