1722011111021 has 2 divisors, whose sum is σ = 1722011111022. Its totient is φ = 1722011111020.

The previous prime is 1722011111017. The next prime is 1722011111039. The reversal of 1722011111021 is 1201111102271.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1172131022500 + 549880088521 = 1082650^2 + 741539^2 .

It is an emirp because it is prime and its reverse (1201111102271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1722011111021 - 2² = 1722011111017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1722011110984 and 1722011111002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1722011111011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 861005555510 + 861005555511.

It is an arithmetic number, because the mean of its divisors is an integer number (861005555511).

Almost surely, 2^{1722011111021} is an apocalyptic number.

It is an amenable number.

1722011111021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1722011111021 is an equidigital number, since it uses as much as digits as its factorization.

1722011111021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 20.

Adding to 1722011111021 its reverse (1201111102271), we get a palindrome (2923122213292).

The spelling of 1722011111021 in words is "one trillion, seven hundred twenty-two billion, eleven million, one hundred eleven thousand, twenty-one".