638311799 has 2 divisors, whose sum is σ = 638311800. Its totient is φ = 638311798.

The previous prime is 638311789. The next prime is 638311813. The reversal of 638311799 is 997113836.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638311799 - 2²⁰ = 637263223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638311759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319155899 + 319155900.

It is an arithmetic number, because the mean of its divisors is an integer number (319155900).

Almost surely, 2^638311799 is an apocalyptic number.

638311799 is a deficient number, since it is larger than the sum of its proper divisors (1).

638311799 is an equidigital number, since it uses as much as digits as its factorization.

638311799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 47.

The square root of 638311799 is about 25264.8332470254. The cubic root of 638311799 is about 861.0154756987.

The spelling of 638311799 in words is "six hundred thirty-eight million, three hundred eleven thousand, seven hundred ninety-nine".