638421541099 has 4 divisors (see below), whose sum is σ = 647167041736. Its totient is φ = 629676040464.

The previous prime is 638421541001. The next prime is 638421541103. The reversal of 638421541099 is 990145124836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 638421541099 - 2¹⁵ = 638421508331 is a prime.

It is a super-2 number, since 2×638421541099² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638421541699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4372750209 + ... + 4372750354.

It is an arithmetic number, because the mean of its divisors is an integer number (161791760434).

Almost surely, 2^638421541099 is an apocalyptic number.

638421541099 is a deficient number, since it is larger than the sum of its proper divisors (8745500637).

638421541099 is an equidigital number, since it uses as much as digits as its factorization.

638421541099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8745500636.

The product of its (nonzero) digits is 1866240, while the sum is 52.

The spelling of 638421541099 in words is "six hundred thirty-eight billion, four hundred twenty-one million, five hundred forty-one thousand, ninety-nine".