638221541 has 2 divisors, whose sum is σ = 638221542. Its totient is φ = 638221540.

The previous prime is 638221513. The next prime is 638221543. The reversal of 638221541 is 145122836.

638221541 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 589081441 + 49140100 = 24271^2 + 7010^2 .

It is a cyclic number.

It is not a de Polignac number, because 638221541 - 2⁶ = 638221477 is a prime.

Together with 638221543, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 638221498 and 638221507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638221543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319110770 + 319110771.

It is an arithmetic number, because the mean of its divisors is an integer number (319110771).

Almost surely, 2^638221541 is an apocalyptic number.

It is an amenable number.

638221541 is a deficient number, since it is larger than the sum of its proper divisors (1).

638221541 is an equidigital number, since it uses as much as digits as its factorization.

638221541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 32.

The square root of 638221541 is about 25263.0469460831. The cubic root of 638221541 is about 860.9748909364.

The spelling of 638221541 in words is "six hundred thirty-eight million, two hundred twenty-one thousand, five hundred forty-one".