1721543 has 2 divisors, whose sum is σ = 1721544. Its totient is φ = 1721542.

The previous prime is 1721521. The next prime is 1721557. The reversal of 1721543 is 3451271.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1721543 - 2¹² = 1717447 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860771 + 860772.

It is an arithmetic number, because the mean of its divisors is an integer number (860772).

2^1721543 is an apocalyptic number.

1721543 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721543 is an equidigital number, since it uses as much as digits as its factorization.

1721543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 23.

The square root of 1721543 is about 1312.0758362229. The cubic root of 1721543 is about 119.8503458486.

The spelling of 1721543 in words is "one million, seven hundred twenty-one thousand, five hundred forty-three".