2112211721 has 2 divisors, whose sum is σ = 2112211722. Its totient is φ = 2112211720.

The previous prime is 2112211709. The next prime is 2112211727. The reversal of 2112211721 is 1271122112.

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., 2057983225 + 54228496 = 45365^2 + 7364^2 .

It is a cyclic number.

It is not a de Polignac number, because 2112211721 - 2³⁰ = 1038469897 is a prime.

It is a super-2 number, since 2×2112211721² = 8922876708659563682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2112211693 and 2112211702.

It is not a weakly prime, because it can be changed into another prime (2112211727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1056105860 + 1056105861.

It is an arithmetic number, because the mean of its divisors is an integer number (1056105861).

Almost surely, 2^2112211721 is an apocalyptic number.

It is an amenable number.

2112211721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2112211721 is an equidigital number, since it uses as much as digits as its factorization.

2112211721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112, while the sum is 20.

The square root of 2112211721 is about 45958.8046080400. The cubic root of 2112211721 is about 1283.0566031905.

Adding to 2112211721 its reverse (1271122112), we get a palindrome (3383333833).

The spelling of 2112211721 in words is "two billion, one hundred twelve million, two hundred eleven thousand, seven hundred twenty-one".