2111100220721 has 2 divisors, whose sum is σ = 2111100220722. Its totient is φ = 2111100220720.

The previous prime is 2111100220661. The next prime is 2111100220769. The reversal of 2111100220721 is 1270220011112.

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., 1353441390625 + 757658830096 = 1163375^2 + 870436^2 .

It is a cyclic number.

It is not a de Polignac number, because 2111100220721 - 2¹⁸ = 2111099958577 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2111100220693 and 2111100220702.

It is not a weakly prime, because it can be changed into another prime (2111100220781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1055550110360 + 1055550110361.

It is an arithmetic number, because the mean of its divisors is an integer number (1055550110361).

Almost surely, 2^{2111100220721} is an apocalyptic number.

It is an amenable number.

2111100220721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2111100220721 is an equidigital number, since it uses as much as digits as its factorization.

2111100220721 is an evil number, because the sum of its binary digits is even.

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

Adding to 2111100220721 its reverse (1270220011112), we get a palindrome (3381320231833).

The spelling of 2111100220721 in words is "two trillion, one hundred eleven billion, one hundred million, two hundred twenty thousand, seven hundred twenty-one".