891908109 has 12 divisors (see below), whose sum is σ = 1290900000. Its totient is φ = 593410824.

The previous prime is 891908093. The next prime is 891908117. The reversal of 891908109 is 901809198.

It is not a de Polignac number, because 891908109 - 2⁴ = 891908093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891908159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94809 + ... + 103790.

It is an arithmetic number, because the mean of its divisors is an integer number (107575000).

Almost surely, 2^891908109 is an apocalyptic number.

It is an amenable number.

891908109 is a deficient number, since it is larger than the sum of its proper divisors (398991891).

891908109 is a wasteful number, since it uses less digits than its factorization.

891908109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199104 (or 199101 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 891908109 is about 29864.8306373902. The cubic root of 891908109 is about 962.5871005452.

The spelling of 891908109 in words is "eight hundred ninety-one million, nine hundred eight thousand, one hundred nine".