638427799 has 2 divisors, whose sum is σ = 638427800. Its totient is φ = 638427798.

The previous prime is 638427781. The next prime is 638427817. The reversal of 638427799 is 997724836.

It is a balanced prime because it is at equal distance from previous prime (638427781) and next prime (638427817).

It is a cyclic number.

It is not a de Polignac number, because 638427799 - 2¹¹ = 638425751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638427709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319213899 + 319213900.

It is an arithmetic number, because the mean of its divisors is an integer number (319213900).

Almost surely, 2^638427799 is an apocalyptic number.

638427799 is a deficient number, since it is larger than the sum of its proper divisors (1).

638427799 is an equidigital number, since it uses as much as digits as its factorization.

638427799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4572288, while the sum is 55.

The square root of 638427799 is about 25267.1288238296. The cubic root of 638427799 is about 861.0676298057.

The spelling of 638427799 in words is "six hundred thirty-eight million, four hundred twenty-seven thousand, seven hundred ninety-nine".