638423 has 2 divisors, whose sum is σ = 638424. Its totient is φ = 638422.

The previous prime is 638371. The next prime is 638431. The reversal of 638423 is 324836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638423 - 2⁶ = 638359 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638392 and 638401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319211 + 319212.

It is an arithmetic number, because the mean of its divisors is an integer number (319212).

2⁶³⁸⁴²³ is an apocalyptic number.

638423 is a deficient number, since it is larger than the sum of its proper divisors (1).

638423 is an equidigital number, since it uses as much as digits as its factorization.

638423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 26.

The square root of 638423 is about 799.0137670904. The cubic root of 638423 is about 86.1065472280.

The spelling of 638423 in words is "six hundred thirty-eight thousand, four hundred twenty-three".