638430870 has 128 divisors (see below), whose sum is σ = 1921646592. Its totient is φ = 131875200.

The previous prime is 638430857. The next prime is 638430883. The reversal of 638430870 is 78034836.

638430870 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (638430857) and next prime (638430883).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 440487 + ... + 441933.

It is an arithmetic number, because the mean of its divisors is an integer number (15012864).

Almost surely, 2^638430870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638430870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (960823296).

638430870 is an abundant number, since it is smaller than the sum of its proper divisors (1283215722).

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

638430870 is a wasteful number, since it uses less digits than its factorization.

638430870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1666.

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 638430870 is about 25267.1895944128. The cubic root of 638430870 is about 861.0690104549.

The spelling of 638430870 in words is "six hundred thirty-eight million, four hundred thirty thousand, eight hundred seventy".