638771016 has 64 divisors (see below), whose sum is σ = 1748013120. Its totient is φ = 193317120.

The previous prime is 638771009. The next prime is 638771069. The reversal of 638771016 is 610177836.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2251 + ... + 35813.

It is an arithmetic number, because the mean of its divisors is an integer number (27312705).

Almost surely, 2^638771016 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 638771016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (874006560).

638771016 is an abundant number, since it is smaller than the sum of its proper divisors (1109242104).

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

638771016 is a wasteful number, since it uses less digits than its factorization.

638771016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33646 (or 33642 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 39.

The square root of 638771016 is about 25273.9196801762. The cubic root of 638771016 is about 861.2219046800.

The spelling of 638771016 in words is "six hundred thirty-eight million, seven hundred seventy-one thousand, sixteen".