638351880 has 64 divisors (see below), whose sum is σ = 1943663040. Its totient is φ = 167684352.

The previous prime is 638351869. The next prime is 638351881. The reversal of 638351880 is 88153836.

It is not an unprimeable number, because it can be changed into a prime (638351881) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 31659 + ... + 47738.

It is an arithmetic number, because the mean of its divisors is an integer number (30369735).

Almost surely, 2^638351880 is an apocalyptic number.

638351880 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638351880 is an abundant number, since it is smaller than the sum of its proper divisors (1305311160).

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

638351880 is a wasteful number, since it uses less digits than its factorization.

638351880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79478 (or 79474 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 638351880 is about 25265.6264517625. The cubic root of 638351880 is about 861.0334970059.

The spelling of 638351880 in words is "six hundred thirty-eight million, three hundred fifty-one thousand, eight hundred eighty".