2191857408 has 360 divisors, whose sum is σ = 7229775168. Its totient is φ = 656252928.

The previous prime is 2191857397. The next prime is 2191857431. The reversal of 2191857408 is 8047581912.

2191857408 is a `hidden beast` number, since 2 + 191 + 8 + 57 + 408 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 12669610 + ... + 12669782.

Almost surely, 2^2191857408 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 2191857408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3614887584).

2191857408 is an abundant number, since it is smaller than the sum of its proper divisors (5037917760).

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

2191857408 is a wasteful number, since it uses less digits than its factorization.

2191857408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The square root of 2191857408 is about 46817.2768110235. The cubic root of 2191857408 is about 1298.9848896044.

The spelling of 2191857408 in words is "two billion, one hundred ninety-one million, eight hundred fifty-seven thousand, four hundred eight".