638940707090 has 32 divisors (see below), whose sum is σ = 1336670156160. Its totient is φ = 215352411264.

The previous prime is 638940707059. The next prime is 638940707099. The reversal of 638940707090 is 90707049836.

It is not an unprimeable number, because it can be changed into a prime (638940707099) 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 15 ways as a sum of consecutive naturals, for example, 77349467 + ... + 77357726.

It is an arithmetic number, because the mean of its divisors is an integer number (41770942380).

Almost surely, 2^638940707090 is an apocalyptic number.

638940707090 is an abundant number, since it is smaller than the sum of its proper divisors (697729449070).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638940707090 is a wasteful number, since it uses less digits than its factorization.

638940707090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154707266.

The product of its (nonzero) digits is 2286144, while the sum is 53.

The spelling of 638940707090 in words is "six hundred thirty-eight billion, nine hundred forty million, seven hundred seven thousand, ninety".