1891945128 has 64 divisors (see below), whose sum is σ = 4888972800. Its totient is φ = 609488640.

The previous prime is 1891945117. The next prime is 1891945141. The reversal of 1891945128 is 8215491981.

It is a happy number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 823950 + ... + 826242.

It is an arithmetic number, because the mean of its divisors is an integer number (76390200).

Almost surely, 2^1891945128 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 1891945128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2444486400).

1891945128 is an abundant number, since it is smaller than the sum of its proper divisors (2997027672).

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

1891945128 is a wasteful number, since it uses less digits than its factorization.

1891945128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3442 (or 3438 counting only the distinct ones).

The product of its digits is 207360, while the sum is 48.

The square root of 1891945128 is about 43496.4955829777. The cubic root of 1891945128 is about 1236.8095941182.

The spelling of 1891945128 in words is "one billion, eight hundred ninety-one million, nine hundred forty-five thousand, one hundred twenty-eight".