2191988860 has 24 divisors (see below), whose sum is σ = 4648756896. Its totient is φ = 868113600.

The previous prime is 2191988819. The next prime is 2191988861. The reversal of 2191988860 is 688891912.

It is a junction number, because it is equal to n+sod(n) for n = 2191988798 and 2191988807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191988861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 540552 + ... + 544591.

It is an arithmetic number, because the mean of its divisors is an integer number (193698204).

Almost surely, 2^2191988860 is an apocalyptic number.

2191988860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2191988860 is an abundant number, since it is smaller than the sum of its proper divisors (2456768036).

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

2191988860 is a wasteful number, since it uses less digits than its factorization.

2191988860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1085253 (or 1085251 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 52.

The square root of 2191988860 is about 46818.6806734235. The cubic root of 2191988860 is about 1299.0108570400.

The spelling of 2191988860 in words is "two billion, one hundred ninety-one million, nine hundred eighty-eight thousand, eight hundred sixty".