1722743821 has 2 divisors, whose sum is σ = 1722743822. Its totient is φ = 1722743820.

The previous prime is 1722743819. The next prime is 1722743833. The reversal of 1722743821 is 1283472271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1583244100 + 139499721 = 39790^2 + 11811^2 .

It is an emirp because it is prime and its reverse (1283472271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1722743821 - 2¹ = 1722743819 is a prime.

Together with 1722743819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1722743881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 861371910 + 861371911.

It is an arithmetic number, because the mean of its divisors is an integer number (861371911).

Almost surely, 2^1722743821 is an apocalyptic number.

It is an amenable number.

1722743821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1722743821 is an equidigital number, since it uses as much as digits as its factorization.

1722743821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37632, while the sum is 37.

The square root of 1722743821 is about 41505.9492241775. The cubic root of 1722743821 is about 1198.7820561604.

The spelling of 1722743821 in words is "one billion, seven hundred twenty-two million, seven hundred forty-three thousand, eight hundred twenty-one".