638309020 has 12 divisors (see below), whose sum is σ = 1340448984. Its totient is φ = 255323600.

The previous prime is 638308999. The next prime is 638309027. The reversal of 638309020 is 20903836.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638309027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15957706 + ... + 15957745.

It is an arithmetic number, because the mean of its divisors is an integer number (111704082).

Almost surely, 2^638309020 is an apocalyptic number.

It is an amenable number.

638309020 is an abundant number, since it is smaller than the sum of its proper divisors (702139964).

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

638309020 is a wasteful number, since it uses less digits than its factorization.

638309020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31915460 (or 31915458 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 638309020 is about 25264.7782495711. The cubic root of 638309020 is about 861.0142261707.

The spelling of 638309020 in words is "six hundred thirty-eight million, three hundred nine thousand, twenty".