1721543423 has 4 divisors (see below), whose sum is σ = 1724204880. Its totient is φ = 1718881968.

The previous prime is 1721543407. The next prime is 1721543459. The reversal of 1721543423 is 3243451271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3243451271 = 193 ⋅16805447.

It is a cyclic number.

It is not a de Polignac number, because 1721543423 - 2⁴ = 1721543407 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1721543423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721543623) 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, 1329758 + ... + 1331051.

It is an arithmetic number, because the mean of its divisors is an integer number (431051220).

Almost surely, 2^1721543423 is an apocalyptic number.

1721543423 is a deficient number, since it is larger than the sum of its proper divisors (2661457).

1721543423 is an equidigital number, since it uses as much as digits as its factorization.

1721543423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2661456.

The product of its digits is 20160, while the sum is 32.

The square root of 1721543423 is about 41491.4861507756. The cubic root of 1721543423 is about 1198.5035566475.

Adding to 1721543423 its reverse (3243451271), we get a palindrome (4964994694).

The spelling of 1721543423 in words is "one billion, seven hundred twenty-one million, five hundred forty-three thousand, four hundred twenty-three".