891265128 has 128 divisors (see below), whose sum is σ = 2535751680. Its totient is φ = 259096320.

The previous prime is 891265087. The next prime is 891265163. The reversal of 891265128 is 821562198.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 891265128.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 414825 + ... + 416967.

It is an arithmetic number, because the mean of its divisors is an integer number (19810560).

Almost surely, 2^891265128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 891265128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1267875840).

891265128 is an abundant number, since it is smaller than the sum of its proper divisors (1644486552).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

891265128 is a wasteful number, since it uses less digits than its factorization.

891265128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2239 (or 2235 counting only the distinct ones).

The product of its digits is 69120, while the sum is 42.

The square root of 891265128 is about 29854.0638439727. The cubic root of 891265128 is about 962.3557336594.

The spelling of 891265128 in words is "eight hundred ninety-one million, two hundred sixty-five thousand, one hundred twenty-eight".