891668899 has 8 divisors (see below), whose sum is σ = 1015022592. Its totient is φ = 775364040.

The previous prime is 891668863. The next prime is 891668929. The reversal of 891668899 is 998866198.

891668899 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 891668899 - 2⁹ = 891668387 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 891668899.

It is not an unprimeable number, because it can be changed into a prime (891669899) 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, 1761939 + ... + 1762444.

It is an arithmetic number, because the mean of its divisors is an integer number (126877824).

Almost surely, 2^891668899 is an apocalyptic number.

891668899 is a deficient number, since it is larger than the sum of its proper divisors (123353693).

891668899 is a wasteful number, since it uses less digits than its factorization.

891668899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3524417.

The product of its digits is 13436928, while the sum is 64.

The square root of 891668899 is about 29860.8254909338. The cubic root of 891668899 is about 962.5010374757.

It can be divided in two parts, 8916 and 68899, that added together give a triangular number (77815 = T₃₉₄).

The spelling of 891668899 in words is "eight hundred ninety-one million, six hundred sixty-eight thousand, eight hundred ninety-nine".