1643423 has 2 divisors, whose sum is σ = 1643424. Its totient is φ = 1643422.

The previous prime is 1643387. The next prime is 1643431. The reversal of 1643423 is 3243461.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1643423 - 2¹⁸ = 1381279 is a prime.

It is a d-powerful number, because it can be written as 1 + 6⁶ + 4³ + 3⁷ + 4³ + 2⁷ + 3¹³ .

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821711 + 821712.

It is an arithmetic number, because the mean of its divisors is an integer number (821712).

2^1643423 is an apocalyptic number.

1643423 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643423 is an equidigital number, since it uses as much as digits as its factorization.

1643423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 23.

The square root of 1643423 is about 1281.9606078191. The cubic root of 1643423 is about 118.0093595947.

Adding to 1643423 its reverse (3243461), we get a palindrome (4886884).

The spelling of 1643423 in words is "one million, six hundred forty-three thousand, four hundred twenty-three".