638773044 has 96 divisors (see below), whose sum is σ = 1839452160. Its totient is φ = 168006528.

The previous prime is 638773021. The next prime is 638773061. The reversal of 638773044 is 440377836.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 638772987 and 638773005.

It is a congruent number.

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, 614277 + ... + 615315.

It is an arithmetic number, because the mean of its divisors is an integer number (19160960).

Almost surely, 2^638773044 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638773044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (919726080).

638773044 is an abundant number, since it is smaller than the sum of its proper divisors (1200679116).

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

638773044 is a wasteful number, since it uses less digits than its factorization.

638773044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1629 (or 1627 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 42.

The square root of 638773044 is about 25273.9598005536. The cubic root of 638773044 is about 861.2228160948. Note that the first 3 decimals are identical.

The spelling of 638773044 in words is "six hundred thirty-eight million, seven hundred seventy-three thousand, forty-four".