638577840 has 160 divisors (see below), whose sum is σ = 2101651200. Its totient is φ = 159943680.

The previous prime is 638577811. The next prime is 638577881. The reversal of 638577840 is 48775836.

638577840 is digitally balanced in base 2 and base 6, because in such bases it contains all the possibile digits an equal number of times.

It is a super-4 number, since 4×638577840⁴ (a number of 36 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 638577840.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 596826 + ... + 597894.

It is an arithmetic number, because the mean of its divisors is an integer number (13135320).

Almost surely, 2^638577840 is an apocalyptic number.

638577840 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 638577840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1050825600).

638577840 is an abundant number, since it is smaller than the sum of its proper divisors (1463073360).

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

638577840 is a wasteful number, since it uses less digits than its factorization.

638577840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235 (or 1229 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 48.

The square root of 638577840 is about 25270.0977441719. The cubic root of 638577840 is about 861.1350795256.

The spelling of 638577840 in words is "six hundred thirty-eight million, five hundred seventy-seven thousand, eight hundred forty".