638820331215 has 16 divisors (see below), whose sum is σ = 1115031851136. Its totient is φ = 309731069600.

The previous prime is 638820331213. The next prime is 638820331301. The reversal of 638820331215 is 512133028836.

It is a happy number.

It is not a de Polignac number, because 638820331215 - 2¹ = 638820331213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638820331211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1935819021 + ... + 1935819350.

It is an arithmetic number, because the mean of its divisors is an integer number (69689490696).

Almost surely, 2^638820331215 is an apocalyptic number.

638820331215 is a deficient number, since it is larger than the sum of its proper divisors (476211519921).

638820331215 is a wasteful number, since it uses less digits than its factorization.

638820331215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3871638390.

The product of its (nonzero) digits is 207360, while the sum is 42.

The spelling of 638820331215 in words is "six hundred thirty-eight billion, eight hundred twenty million, three hundred thirty-one thousand, two hundred fifteen".