1721749 has 2 divisors, whose sum is σ = 1721750. Its totient is φ = 1721748.

The previous prime is 1721729. The next prime is 1721767. The reversal of 1721749 is 9471271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1512900 + 208849 = 1230^2 + 457^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721749 - 2⁵ = 1721717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1721749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860874 + 860875.

It is an arithmetic number, because the mean of its divisors is an integer number (860875).

2^1721749 is an apocalyptic number.

It is an amenable number.

1721749 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721749 is an equidigital number, since it uses as much as digits as its factorization.

1721749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3528, while the sum is 31.

The square root of 1721749 is about 1312.1543354347. The cubic root of 1721749 is about 119.8551260926.

The spelling of 1721749 in words is "one million, seven hundred twenty-one thousand, seven hundred forty-nine".