638212340 has 12 divisors (see below), whose sum is σ = 1340245956. Its totient is φ = 255284928.

The previous prime is 638212327. The next prime is 638212343. The reversal of 638212340 is 43212836.

It can be written as a sum of positive squares in 2 ways, for example, as 76143076 + 562069264 = 8726^2 + 23708^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638212343) 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 3 ways as a sum of consecutive naturals, for example, 15955289 + ... + 15955328.

It is an arithmetic number, because the mean of its divisors is an integer number (111687163).

Almost surely, 2^638212340 is an apocalyptic number.

It is an amenable number.

638212340 is an abundant number, since it is smaller than the sum of its proper divisors (702033616).

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

638212340 is a wasteful number, since it uses less digits than its factorization.

638212340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31910626 (or 31910624 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 638212340 is about 25262.8648415020. The cubic root of 638212340 is about 860.9707534661.

The spelling of 638212340 in words is "six hundred thirty-eight million, two hundred twelve thousand, three hundred forty".