8891993987 has 4 divisors (see below), whose sum is σ = 8907142776. Its totient is φ = 8876845200.

The previous prime is 8891993953. The next prime is 8891994011. The reversal of 8891993987 is 7893991988.

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 8891993987 - 2⁶ = 8891993923 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8891993987.

It is not an unprimeable number, because it can be changed into a prime (8891993917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7573514 + ... + 7574687.

It is an arithmetic number, because the mean of its divisors is an integer number (2226785694).

Almost surely, 2^8891993987 is an apocalyptic number.

8891993987 is a deficient number, since it is larger than the sum of its proper divisors (15148789).

8891993987 is a wasteful number, since it uses less digits than its factorization.

8891993987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15148788.

The product of its digits is 70543872, while the sum is 71.

The square root of 8891993987 is about 94297.3699898359. The cubic root of 8891993987 is about 2071.7295157663.

The spelling of 8891993987 in words is "eight billion, eight hundred ninety-one million, nine hundred ninety-three thousand, nine hundred eighty-seven".