638245660 has 24 divisors (see below), whose sum is σ = 1443417696. Its totient is φ = 235659840.

The previous prime is 638245609. The next prime is 638245667. The reversal of 638245660 is 66542836.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638245667) 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, 1227136 + ... + 1227655.

It is an arithmetic number, because the mean of its divisors is an integer number (60142404).

Almost surely, 2^638245660 is an apocalyptic number.

It is an amenable number.

638245660 is an abundant number, since it is smaller than the sum of its proper divisors (805172036).

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

638245660 is a wasteful number, since it uses less digits than its factorization.

638245660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2454813 (or 2454811 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 638245660 is about 25263.5242988780. The cubic root of 638245660 is about 860.9857364868.

The spelling of 638245660 in words is "six hundred thirty-eight million, two hundred forty-five thousand, six hundred sixty".