638610101 has 2 divisors, whose sum is σ = 638610102. Its totient is φ = 638610100.

The previous prime is 638610079. The next prime is 638610107. The reversal of 638610101 is 101016836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635544100 + 3066001 = 25210^2 + 1751^2 .

It is a cyclic number.

It is not a de Polignac number, because 638610101 - 2¹⁰ = 638609077 is a prime.

It is a super-2 number, since 2×638610101² = 815645722198460402, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638610107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319305050 + 319305051.

It is an arithmetic number, because the mean of its divisors is an integer number (319305051).

Almost surely, 2^638610101 is an apocalyptic number.

It is an amenable number.

638610101 is a deficient number, since it is larger than the sum of its proper divisors (1).

638610101 is an equidigital number, since it uses as much as digits as its factorization.

638610101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 638610101 is about 25270.7360597194. The cubic root of 638610101 is about 861.1495808175.

Adding to 638610101 its reverse (101016836), we get a palindrome (739626937).

The spelling of 638610101 in words is "six hundred thirty-eight million, six hundred ten thousand, one hundred one".