2191289821 has 8 divisors (see below), whose sum is σ = 2504779200. Its totient is φ = 1877912448.

The previous prime is 2191289797. The next prime is 2191289831. The reversal of 2191289821 is 1289821912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2191289821 - 2²¹ = 2189192669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191289831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19245 + ... + 68941.

It is an arithmetic number, because the mean of its divisors is an integer number (313097400).

Almost surely, 2^2191289821 is an apocalyptic number.

It is an amenable number.

2191289821 is a deficient number, since it is larger than the sum of its proper divisors (313489379).

2191289821 is an equidigital number, since it uses as much as digits as its factorization.

2191289821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56003.

The product of its digits is 41472, while the sum is 43.

The square root of 2191289821 is about 46811.2146926354. The cubic root of 2191289821 is about 1298.8727547877.

The spelling of 2191289821 in words is "two billion, one hundred ninety-one million, two hundred eighty-nine thousand, eight hundred twenty-one".