638680241 has 2 divisors, whose sum is σ = 638680242. Its totient is φ = 638680240.

The previous prime is 638680223. The next prime is 638680243. The reversal of 638680241 is 142086836.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 600054016 + 38626225 = 24496^2 + 6215^2 .

It is a cyclic number.

It is not a de Polignac number, because 638680241 - 2⁶ = 638680177 is a prime.

Together with 638680243, 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 = 638680195 and 638680204.

It is not a weakly prime, because it can be changed into another prime (638680243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319340120 + 319340121.

It is an arithmetic number, because the mean of its divisors is an integer number (319340121).

Almost surely, 2^638680241 is an apocalyptic number.

It is an amenable number.

638680241 is a deficient number, since it is larger than the sum of its proper divisors (1).

638680241 is an equidigital number, since it uses as much as digits as its factorization.

638680241 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 638680241 is about 25272.1237928275. The cubic root of 638680241 is about 861.1811070024.

The spelling of 638680241 in words is "six hundred thirty-eight million, six hundred eighty thousand, two hundred forty-one".