891109171 has 4 divisors (see below), whose sum is σ = 929853072. Its totient is φ = 852365272.

The previous prime is 891109103. The next prime is 891109181. The reversal of 891109171 is 171901198.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-891109171 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 891109171.

It is not an unprimeable number, because it can be changed into a prime (891109181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19371916 + ... + 19371961.

It is an arithmetic number, because the mean of its divisors is an integer number (232463268).

Almost surely, 2^891109171 is an apocalyptic number.

891109171 is a deficient number, since it is larger than the sum of its proper divisors (38743901).

891109171 is a wasteful number, since it uses less digits than its factorization.

891109171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38743900.

The product of its (nonzero) digits is 4536, while the sum is 37.

The square root of 891109171 is about 29851.4517402420. The cubic root of 891109171 is about 962.2995981491.

The spelling of 891109171 in words is "eight hundred ninety-one million, one hundred nine thousand, one hundred seventy-one".