638544450 has 24 divisors (see below), whose sum is σ = 1583590608. Its totient is φ = 170278480.

The previous prime is 638544449. The next prime is 638544451. The reversal of 638544450 is 54445836.

It is an interprime number because it is at equal distance from previous prime (638544449) and next prime (638544451).

It is a junction number, because it is equal to n+sod(n) for n = 638544399 and 638544408.

It is not an unprimeable number, because it can be changed into a prime (638544451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2128332 + ... + 2128631.

It is an arithmetic number, because the mean of its divisors is an integer number (65982942).

Almost surely, 2^638544450 is an apocalyptic number.

638544450 is an abundant number, since it is smaller than the sum of its proper divisors (945046158).

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

638544450 is a wasteful number, since it uses less digits than its factorization.

638544450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4256978 (or 4256973 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 39.

The square root of 638544450 is about 25269.4370732709. The cubic root of 638544450 is about 861.1200702348.

The spelling of 638544450 in words is "six hundred thirty-eight million, five hundred forty-four thousand, four hundred fifty".