638746860 has 72 divisors (see below), whose sum is σ = 1818926928. Its totient is φ = 167481600.

The previous prime is 638746819. The next prime is 638746939. The reversal of 638746860 is 68647836.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 221830 + ... + 224690.

It is an arithmetic number, because the mean of its divisors is an integer number (25262874).

Almost surely, 2^638746860 is an apocalyptic number.

638746860 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 638746860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909463464).

638746860 is an abundant number, since it is smaller than the sum of its proper divisors (1180180068).

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

638746860 is a wasteful number, since it uses less digits than its factorization.

638746860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2995 (or 2932 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 48.

The square root of 638746860 is about 25273.4417917307. The cubic root of 638746860 is about 861.2110484482.

The spelling of 638746860 in words is "six hundred thirty-eight million, seven hundred forty-six thousand, eight hundred sixty".