1721541 has 4 divisors (see below), whose sum is σ = 2295392. Its totient is φ = 1147692.

The previous prime is 1721521. The next prime is 1721543. The reversal of 1721541 is 1451271.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1451271 = 3 ⋅483757.

It is not a de Polignac number, because 1721541 - 2⁵ = 1721509 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

1721541 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 286921 + ... + 286926.

It is an arithmetic number, because the mean of its divisors is an integer number (573848).

2^1721541 is an apocalyptic number.

It is an amenable number.

1721541 is a deficient number, since it is larger than the sum of its proper divisors (573851).

1721541 is an equidigital number, since it uses as much as digits as its factorization.

1721541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573850.

The product of its digits is 280, while the sum is 21.

The square root of 1721541 is about 1312.0750740716. The cubic root of 1721541 is about 119.8502994366.

The spelling of 1721541 in words is "one million, seven hundred twenty-one thousand, five hundred forty-one".