638527261 has 2 divisors, whose sum is σ = 638527262. Its totient is φ = 638527260.

The previous prime is 638527247. The next prime is 638527291. The reversal of 638527261 is 162725836.

638527261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 638522361 + 4900 = 25269^2 + 70^2 .

It is a cyclic number.

It is not a de Polignac number, because 638527261 - 2¹¹ = 638525213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638527291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319263630 + 319263631.

It is an arithmetic number, because the mean of its divisors is an integer number (319263631).

Almost surely, 2^638527261 is an apocalyptic number.

It is an amenable number.

638527261 is a deficient number, since it is larger than the sum of its proper divisors (1).

638527261 is an equidigital number, since it uses as much as digits as its factorization.

638527261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 40.

The square root of 638527261 is about 25269.0969565594. The cubic root of 638527261 is about 861.1123433252.

The spelling of 638527261 in words is "six hundred thirty-eight million, five hundred twenty-seven thousand, two hundred sixty-one".