638708224 has 160 divisors (see below), whose sum is σ = 1686427776. Its totient is φ = 233963520.

The previous prime is 638708219. The next prime is 638708263. The reversal of 638708224 is 422807836.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 669732 + ... + 670684.

Almost surely, 2^638708224 is an apocalyptic number.

638708224 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638708224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (843213888).

638708224 is an abundant number, since it is smaller than the sum of its proper divisors (1047719552).

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

638708224 is a wasteful number, since it uses less digits than its factorization.

638708224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1006 (or 990 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 40.

The square root of 638708224 is about 25272.6774204871. The cubic root of 638708224 is about 861.1936840205.

The spelling of 638708224 in words is "six hundred thirty-eight million, seven hundred eight thousand, two hundred twenty-four".