891556987889 has 8 divisors (see below), whose sum is σ = 894323562600. Its totient is φ = 888791129856.

The previous prime is 891556987819. The next prime is 891556987891. The reversal of 891556987889 is 988789655198.

It is a happy number.

891556987889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 147788731489 + 743768256400 = 384433^2 + 862420^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-891556987889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (891556987819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2368787 + ... + 2719239.

It is an arithmetic number, because the mean of its divisors is an integer number (111790445325).

Almost surely, 2^891556987889 is an apocalyptic number.

It is an amenable number.

891556987889 is a deficient number, since it is larger than the sum of its proper divisors (2766574711).

891556987889 is a wasteful number, since it uses less digits than its factorization.

891556987889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358339.

The product of its digits is 3135283200, while the sum is 83.

The spelling of 891556987889 in words is "eight hundred ninety-one billion, five hundred fifty-six million, nine hundred eighty-seven thousand, eight hundred eighty-nine".