2211122721 has 4 divisors (see below), whose sum is σ = 2948163632. Its totient is φ = 1474081812.

The previous prime is 2211122717. The next prime is 2211122729. The reversal of 2211122721 is 1272211122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2211122721 - 2² = 2211122717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2211122729) 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 3 ways as a sum of consecutive naturals, for example, 368520451 + ... + 368520456.

It is an arithmetic number, because the mean of its divisors is an integer number (737040908).

Almost surely, 2^2211122721 is an apocalyptic number.

It is an amenable number.

2211122721 is a deficient number, since it is larger than the sum of its proper divisors (737040911).

2211122721 is an equidigital number, since it uses as much as digits as its factorization.

2211122721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737040910.

The product of its digits is 224, while the sum is 21.

The square root of 2211122721 is about 47022.5767158713. The cubic root of 2211122721 is about 1302.7795991039.

Adding to 2211122721 its reverse (1272211122), we get a palindrome (3483333843).

The spelling of 2211122721 in words is "two billion, two hundred eleven million, one hundred twenty-two thousand, seven hundred twenty-one".