1721149 has 2 divisors, whose sum is σ = 1721150. Its totient is φ = 1721148.

The previous prime is 1721147. The next prime is 1721183. The reversal of 1721149 is 9411271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1464100 + 257049 = 1210^2 + 507^2 .

It is an emirp because it is prime and its reverse (9411271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1721149 - 2¹ = 1721147 is a prime.

Together with 1721147, 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 (1721143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860574 + 860575.

It is an arithmetic number, because the mean of its divisors is an integer number (860575).

2^1721149 is an apocalyptic number.

It is an amenable number.

1721149 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721149 is an equidigital number, since it uses as much as digits as its factorization.

1721149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504, while the sum is 25.

The square root of 1721149 is about 1311.9256838709. The cubic root of 1721149 is about 119.8412019897.

The spelling of 1721149 in words is "one million, seven hundred twenty-one thousand, one hundred forty-nine".