1721905349 has 2 divisors, whose sum is σ = 1721905350. Its totient is φ = 1721905348.

The previous prime is 1721905291. The next prime is 1721905351. The reversal of 1721905349 is 9435091271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 925254724 + 796650625 = 30418^2 + 28225^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1721905349 is a prime.

Together with 1721905351, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721905369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860952674 + 860952675.

It is an arithmetic number, because the mean of its divisors is an integer number (860952675).

Almost surely, 2^1721905349 is an apocalyptic number.

It is an amenable number.

1721905349 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721905349 is an equidigital number, since it uses as much as digits as its factorization.

1721905349 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040, while the sum is 41.

The square root of 1721905349 is about 41495.8473705502. The cubic root of 1721905349 is about 1198.5875392719.

The spelling of 1721905349 in words is "one billion, seven hundred twenty-one million, nine hundred five thousand, three hundred forty-nine".