2191694656 has 56 divisors (see below), whose sum is σ = 4549834944. Its totient is φ = 1045524480.

The previous prime is 2191694629. The next prime is 2191694657. The reversal of 2191694656 is 6564961912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191694657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 650416 + ... + 653776.

Almost surely, 2^2191694656 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 2191694656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2274917472).

2191694656 is an abundant number, since it is smaller than the sum of its proper divisors (2358140288).

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

2191694656 is a wasteful number, since it uses less digits than its factorization.

2191694656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3839 (or 3829 counting only the distinct ones).

The product of its digits is 699840, while the sum is 49.

The square root of 2191694656 is about 46815.5386170019. The cubic root of 2191694656 is about 1298.9527376313.

The spelling of 2191694656 in words is "two billion, one hundred ninety-one million, six hundred ninety-four thousand, six hundred fifty-six".