2199209921 has 2 divisors, whose sum is σ = 2199209922. Its totient is φ = 2199209920.

The previous prime is 2199209897. The next prime is 2199209923. The reversal of 2199209921 is 1299029912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2070705025 + 128504896 = 45505^2 + 11336^2 .

It is a cyclic number.

It is not a de Polignac number, because 2199209921 - 2²⁶ = 2132101057 is a prime.

Together with 2199209923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2199209923) 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 as a sum of consecutive naturals, namely, 1099604960 + 1099604961.

It is an arithmetic number, because the mean of its divisors is an integer number (1099604961).

Almost surely, 2^2199209921 is an apocalyptic number.

It is an amenable number.

2199209921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2199209921 is an equidigital number, since it uses as much as digits as its factorization.

2199209921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 44.

The square root of 2199209921 is about 46895.7345714938. The cubic root of 2199209921 is about 1300.4357357872.

Subtracting from 2199209921 its reverse (1299029912), we obtain a square (900180009 = 30003²).

The spelling of 2199209921 in words is "two billion, one hundred ninety-nine million, two hundred nine thousand, nine hundred twenty-one".