638274643 has 4 divisors (see below), whose sum is σ = 642933720. Its totient is φ = 633615568.

The previous prime is 638274589. The next prime is 638274653. The reversal of 638274643 is 346472836.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638274643 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638274643.

It is not an unprimeable number, because it can be changed into a prime (638274653) 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, 2329333 + ... + 2329606.

It is an arithmetic number, because the mean of its divisors is an integer number (160733430).

Almost surely, 2^638274643 is an apocalyptic number.

638274643 is a deficient number, since it is larger than the sum of its proper divisors (4659077).

638274643 is a wasteful number, since it uses less digits than its factorization.

638274643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4659076.

The product of its digits is 580608, while the sum is 43.

The square root of 638274643 is about 25264.0979059218. The cubic root of 638274643 is about 860.9987688626.

The spelling of 638274643 in words is "six hundred thirty-eight million, two hundred seventy-four thousand, six hundred forty-three".