638364402 has 144 divisors (see below), whose sum is σ = 1623218688. Its totient is φ = 186896160.

The previous prime is 638364373. The next prime is 638364407. The reversal of 638364402 is 204463836.

It is a happy number.

638364402 is a `hidden beast` number, since 6 + 3 + 8 + 3 + 644 + 0 + 2 = 666.

It is not an unprimeable number, because it can be changed into a prime (638364407) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3342127 + ... + 3342317.

It is an arithmetic number, because the mean of its divisors is an integer number (11272352).

Almost surely, 2^638364402 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638364402, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (811609344).

638364402 is an abundant number, since it is smaller than the sum of its proper divisors (984854286).

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

638364402 is a wasteful number, since it uses less digits than its factorization.

638364402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267 (or 232 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 638364402 is about 25265.8742575831. The cubic root of 638364402 is about 861.0391270204.

The spelling of 638364402 in words is "six hundred thirty-eight million, three hundred sixty-four thousand, four hundred two".