638453820 has 24 divisors (see below), whose sum is σ = 1787670864. Its totient is φ = 170254336.

The previous prime is 638453801. The next prime is 638453861. The reversal of 638453820 is 28354836.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 5320389 + ... + 5320508.

It is an arithmetic number, because the mean of its divisors is an integer number (74486286).

Almost surely, 2^638453820 is an apocalyptic number.

638453820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638453820 is an abundant number, since it is smaller than the sum of its proper divisors (1149217044).

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

638453820 is a wasteful number, since it uses less digits than its factorization.

638453820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10640909 (or 10640907 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 39.

The square root of 638453820 is about 25267.6437366051. The cubic root of 638453820 is about 861.0793280935.

The spelling of 638453820 in words is "six hundred thirty-eight million, four hundred fifty-three thousand, eight hundred twenty".