1721023 has 2 divisors, whose sum is σ = 1721024. Its totient is φ = 1721022.

The previous prime is 1721011. The next prime is 1721081. The reversal of 1721023 is 3201271.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (3201271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1721023 - 2⁵ = 1720991 is a prime.

It is an Ulam number.

1721023 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1720988 and 1721006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860511 + 860512.

It is an arithmetic number, because the mean of its divisors is an integer number (860512).

2^1721023 is an apocalyptic number.

1721023 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721023 is an equidigital number, since it uses as much as digits as its factorization.

1721023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 1721023 is about 1311.8776619792. The cubic root of 1721023 is about 119.8382775169.

Adding to 1721023 its reverse (3201271), we get a palindrome (4922294).

The spelling of 1721023 in words is "one million, seven hundred twenty-one thousand, twenty-three".