638546641 has 2 divisors, whose sum is σ = 638546642. Its totient is φ = 638546640.

The previous prime is 638546627. The next prime is 638546647. The reversal of 638546641 is 146645836.

It is a happy number.

638546641 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., 588547600 + 49999041 = 24260^2 + 7071^2 .

It is a cyclic number.

It is not a de Polignac number, because 638546641 - 2¹³ = 638538449 is a prime.

It is not a weakly prime, because it can be changed into another prime (638546647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319273320 + 319273321.

It is an arithmetic number, because the mean of its divisors is an integer number (319273321).

Almost surely, 2^638546641 is an apocalyptic number.

It is an amenable number.

638546641 is a deficient number, since it is larger than the sum of its proper divisors (1).

638546641 is an equidigital number, since it uses as much as digits as its factorization.

638546641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 414720, while the sum is 43.

The square root of 638546641 is about 25269.4804260001. The cubic root of 638546641 is about 861.1210551372.

The spelling of 638546641 in words is "six hundred thirty-eight million, five hundred forty-six thousand, six hundred forty-one".