638220492 has 144 divisors (see below), whose sum is σ = 2073076320. Its totient is φ = 168303744.

The previous prime is 638220463. The next prime is 638220509. The reversal of 638220492 is 294022836.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64158 + ... + 73434.

Almost surely, 2^638220492 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 638220492, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1036538160).

638220492 is an abundant number, since it is smaller than the sum of its proper divisors (1434855828).

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

638220492 is a wasteful number, since it uses less digits than its factorization.

638220492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9317 (or 9302 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 638220492 is about 25263.0261845251. The cubic root of 638220492 is about 860.9744192281.

The spelling of 638220492 in words is "six hundred thirty-eight million, two hundred twenty thousand, four hundred ninety-two".