641321638 has 4 divisors (see below), whose sum is σ = 961982460. Its totient is φ = 320660818.

The previous prime is 641321633. The next prime is 641321647. The reversal of 641321638 is 836123146.

It is a happy number.

641321638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-2 number, since 2×641321638² = 822586886734006088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641321633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160330408 + ... + 160330411.

It is an arithmetic number, because the mean of its divisors is an integer number (240495615).

Almost surely, 2^641321638 is an apocalyptic number.

641321638 is a deficient number, since it is larger than the sum of its proper divisors (320660822).

641321638 is a wasteful number, since it uses less digits than its factorization.

641321638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320660821.

The product of its digits is 20736, while the sum is 34.

The square root of 641321638 is about 25324.3289743282. The cubic root of 641321638 is about 862.3666728868.

The spelling of 641321638 in words is "six hundred forty-one million, three hundred twenty-one thousand, six hundred thirty-eight".