638629 has 2 divisors, whose sum is σ = 638630. Its totient is φ = 638628.

The previous prime is 638621. The next prime is 638633. The reversal of 638629 is 926836.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 390625 + 248004 = 625^2 + 498^2 .

It is a cyclic number.

It is not a de Polignac number, because 638629 - 2³ = 638621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638594 and 638603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319314 + 319315.

It is an arithmetic number, because the mean of its divisors is an integer number (319315).

2⁶³⁸⁶²⁹ is an apocalyptic number.

It is an amenable number.

638629 is a deficient number, since it is larger than the sum of its proper divisors (1).

638629 is an equidigital number, since it uses as much as digits as its factorization.

638629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 34.

The square root of 638629 is about 799.1426656111. The cubic root of 638629 is about 86.1158075675.

The spelling of 638629 in words is "six hundred thirty-eight thousand, six hundred twenty-nine".