638443799 has 8 divisors (see below), whose sum is σ = 729813888. Its totient is φ = 547114680.

The previous prime is 638443781. The next prime is 638443801. The reversal of 638443799 is 997344836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-638443799 is a prime.

It is a super-2 number, since 2×638443799² = 815220968963104802, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638443799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638443199) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38864 + ... + 52794.

It is an arithmetic number, because the mean of its divisors is an integer number (91226736).

Almost surely, 2^638443799 is an apocalyptic number.

638443799 is a deficient number, since it is larger than the sum of its proper divisors (91370089).

638443799 is a wasteful number, since it uses less digits than its factorization.

638443799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20485.

The product of its digits is 3919104, while the sum is 53.

The square root of 638443799 is about 25267.4454387459. The cubic root of 638443799 is about 861.0748229798.

The spelling of 638443799 in words is "six hundred thirty-eight million, four hundred forty-three thousand, seven hundred ninety-nine".