638475642 has 64 divisors (see below), whose sum is σ = 1625702400. Its totient is φ = 181951920.

The previous prime is 638475619. The next prime is 638475671. The reversal of 638475642 is 246574836.

638475642 is a `hidden beast` number, since 6 + 3 + 84 + 7 + 564 + 2 = 666.

It is a super-2 number, since 2×638475642² = 815302290854624328, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 160959 + ... + 164877.

It is an arithmetic number, because the mean of its divisors is an integer number (25401600).

Almost surely, 2^638475642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638475642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (812851200).

638475642 is an abundant number, since it is smaller than the sum of its proper divisors (987226758).

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

638475642 is a wasteful number, since it uses less digits than its factorization.

638475642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4368 (or 4362 counting only the distinct ones).

The product of its digits is 967680, while the sum is 45.

The square root of 638475642 is about 25268.0755499900. The cubic root of 638475642 is about 861.0891383875.

The spelling of 638475642 in words is "six hundred thirty-eight million, four hundred seventy-five thousand, six hundred forty-two".