2191064256 has 140 divisors (see below), whose sum is σ = 6537367672. Its totient is φ = 725594112.

The previous prime is 2191064243. The next prime is 2191064257. The reversal of 2191064256 is 6524601912.

2191064256 is a `hidden beast` number, since 2 + 1 + 9 + 1 + 0 + 642 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 2191064256.

It is not an unprimeable number, because it can be changed into a prime (2191064257) 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 19 ways as a sum of consecutive naturals, for example, 843696 + ... + 846288.

Almost surely, 2^2191064256 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 2191064256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3268683836).

2191064256 is an abundant number, since it is smaller than the sum of its proper divisors (4346303416).

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

2191064256 is a wasteful number, since it uses less digits than its factorization.

2191064256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2780 (or 2761 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 2191064256 is about 46808.8053254940. The cubic root of 2191064256 is about 1298.8281858640.

The spelling of 2191064256 in words is "two billion, one hundred ninety-one million, sixty-four thousand, two hundred fifty-six".