638323836 has 12 divisors (see below), whose sum is σ = 1489422312. Its totient is φ = 212774608.

The previous prime is 638323817. The next prime is 638323841.

638323836 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26596815 + ... + 26596838.

It is an arithmetic number, because the mean of its divisors is an integer number (124118526).

Almost surely, 2^638323836 is an apocalyptic number.

It is an amenable number.

638323836 is an abundant number, since it is smaller than the sum of its proper divisors (851098476).

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

638323836 is a wasteful number, since it uses less digits than its factorization.

638323836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53193660 (or 53193658 counting only the distinct ones).

The product of its digits is 373248, while the sum is 42.

The square root of 638323836 is about 25265.0714623965. The cubic root of 638323836 is about 861.0208878803.

The spelling of 638323836 in words is "six hundred thirty-eight million, three hundred twenty-three thousand, eight hundred thirty-six".