1722212611661 has 2 divisors, whose sum is σ = 1722212611662. Its totient is φ = 1722212611660.

The previous prime is 1722212611633. The next prime is 1722212611667. The reversal of 1722212611661 is 1661162122271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1677558582436 + 44654029225 = 1295206^2 + 211315^2 .

It is an emirp because it is prime and its reverse (1661162122271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1722212611661 - 2²² = 1722208417357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1722212611667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 861106305830 + 861106305831.

It is an arithmetic number, because the mean of its divisors is an integer number (861106305831).

Almost surely, 2^{1722212611661} is an apocalyptic number.

It is an amenable number.

1722212611661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1722212611661 is an equidigital number, since it uses as much as digits as its factorization.

1722212611661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 38.

The spelling of 1722212611661 in words is "one trillion, seven hundred twenty-two billion, two hundred twelve million, six hundred eleven thousand, six hundred sixty-one".