638101309 has 2 divisors, whose sum is σ = 638101310. Its totient is φ = 638101308.

The previous prime is 638101283. The next prime is 638101357. The reversal of 638101309 is 903101836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 414000409 + 224100900 = 20347^2 + 14970^2 .

It is a cyclic number.

It is not a de Polignac number, because 638101309 - 2¹⁹ = 637577021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638101379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319050654 + 319050655.

It is an arithmetic number, because the mean of its divisors is an integer number (319050655).

Almost surely, 2^638101309 is an apocalyptic number.

It is an amenable number.

638101309 is a deficient number, since it is larger than the sum of its proper divisors (1).

638101309 is an equidigital number, since it uses as much as digits as its factorization.

638101309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 638101309 is about 25260.6672318844. The cubic root of 638101309 is about 860.9208223372.

The spelling of 638101309 in words is "six hundred thirty-eight million, one hundred one thousand, three hundred nine".