638258940 has 144 divisors (see below), whose sum is σ = 2190464640. Its totient is φ = 154716480.

The previous prime is 638258939. The next prime is 638258987. The reversal of 638258940 is 49852836.

638258940 is a `hidden beast` number, since 63 + 8 + 2 + 589 + 4 + 0 = 666.

638258940 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 47491 + ... + 59429.

It is an arithmetic number, because the mean of its divisors is an integer number (15211560).

Almost surely, 2^638258940 is an apocalyptic number.

638258940 is a gapful number since it is divisible by the number (60) 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 638258940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1095232320).

638258940 is an abundant number, since it is smaller than the sum of its proper divisors (1552205700).

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

638258940 is a wasteful number, since it uses less digits than its factorization.

638258940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11974 (or 11960 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 45.

The square root of 638258940 is about 25263.7871270322. The cubic root of 638258940 is about 860.9917079656.

The spelling of 638258940 in words is "six hundred thirty-eight million, two hundred fifty-eight thousand, nine hundred forty".