1721423 has 4 divisors (see below), whose sum is σ = 1877928. Its totient is φ = 1564920.

The previous prime is 1721417. The next prime is 1721441. The reversal of 1721423 is 3241271.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1721423 - 2⁴ = 1721407 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1721395 and 1721404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721453) 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, 78236 + ... + 78257.

It is an arithmetic number, because the mean of its divisors is an integer number (469482).

2^1721423 is an apocalyptic number.

1721423 is a deficient number, since it is larger than the sum of its proper divisors (156505).

1721423 is a wasteful number, since it uses less digits than its factorization.

1721423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156504.

The product of its digits is 336, while the sum is 20.

The square root of 1721423 is about 1312.0301063619. The cubic root of 1721423 is about 119.8475610647.

Adding to 1721423 its reverse (3241271), we get a palindrome (4962694).

The spelling of 1721423 in words is "one million, seven hundred twenty-one thousand, four hundred twenty-three".