638429428 has 72 divisors (see below), whose sum is σ = 1432429152. Its totient is φ = 246649536.

The previous prime is 638429419. The next prime is 638429479. The reversal of 638429428 is 824924836.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 106651 + ... + 112477.

Almost surely, 2^638429428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638429428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (716214576).

638429428 is an abundant number, since it is smaller than the sum of its proper divisors (793999724).

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

638429428 is a wasteful number, since it uses less digits than its factorization.

638429428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5901 (or 5892 counting only the distinct ones).

The product of its digits is 663552, while the sum is 46.

The square root of 638429428 is about 25267.1610593672. The cubic root of 638429428 is about 861.0683621662.

The spelling of 638429428 in words is "six hundred thirty-eight million, four hundred twenty-nine thousand, four hundred twenty-eight".