2191820217 has 24 divisors (see below), whose sum is σ = 3108352896. Its totient is φ = 1373530368.

The previous prime is 2191820201. The next prime is 2191820233. The reversal of 2191820217 is 7120281912.

It is an interprime number because it is at equal distance from previous prime (2191820201) and next prime (2191820233).

It is not a de Polignac number, because 2191820217 - 2⁴ = 2191820201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2191820237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1371663 + ... + 1373259.

It is an arithmetic number, because the mean of its divisors is an integer number (129514704).

Almost surely, 2^2191820217 is an apocalyptic number.

It is an amenable number.

2191820217 is a deficient number, since it is larger than the sum of its proper divisors (916532679).

2191820217 is a wasteful number, since it uses less digits than its factorization.

2191820217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3217 (or 3200 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 2191820217 is about 46816.8796162239. The cubic root of 2191820217 is about 1298.9775425906.

The spelling of 2191820217 in words is "two billion, one hundred ninety-one million, eight hundred twenty thousand, two hundred seventeen".