638767836 has 96 divisors (see below), whose sum is σ = 1907834880. Its totient is φ = 181040832.

The previous prime is 638767813. The next prime is 638767837.

638767836 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638767837) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92686 + ... + 99338.

It is an arithmetic number, because the mean of its divisors is an integer number (19873280).

Almost surely, 2^638767836 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 638767836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (953917440).

638767836 is an abundant number, since it is smaller than the sum of its proper divisors (1269067044).

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

638767836 is a wasteful number, since it uses less digits than its factorization.

638767836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6800 (or 6792 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 54.

The square root of 638767836 is about 25273.8567693971. The cubic root of 638767836 is about 861.2204755345.

The spelling of 638767836 in words is "six hundred thirty-eight million, seven hundred sixty-seven thousand, eight hundred thirty-six".