2191687680 has 512 divisors, whose sum is σ = 8807904000. Its totient is φ = 462422016.

The previous prime is 2191687679. The next prime is 2191687697. The reversal of 2191687680 is 867861912.

It is a tau number, because it is divible by the number of its divisors (512).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

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, 168591354 + ... + 168591366.

Almost surely, 2^2191687680 is an apocalyptic number.

2191687680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2191687680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4403952000).

2191687680 is an abundant number, since it is smaller than the sum of its proper divisors (6616216320).

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

2191687680 is an frugal number, since it uses more digits than its factorization.

2191687680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 48.

The square root of 2191687680 is about 46815.4641117655. The cubic root of 2191687680 is about 1298.9513594734.

The spelling of 2191687680 in words is "two billion, one hundred ninety-one million, six hundred eighty-seven thousand, six hundred eighty".