638787241 has 2 divisors, whose sum is σ = 638787242. Its totient is φ = 638787240.

The previous prime is 638787221. The next prime is 638787269. The reversal of 638787241 is 142787836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 503553600 + 135233641 = 22440^2 + 11629^2 .

It is a cyclic number.

It is not a de Polignac number, because 638787241 - 2⁷ = 638787113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638787191 and 638787200.

It is not a weakly prime, because it can be changed into another prime (638787221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319393620 + 319393621.

It is an arithmetic number, because the mean of its divisors is an integer number (319393621).

Almost surely, 2^638787241 is an apocalyptic number.

It is an amenable number.

638787241 is a deficient number, since it is larger than the sum of its proper divisors (1).

638787241 is an equidigital number, since it uses as much as digits as its factorization.

638787241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 451584, while the sum is 46.

The square root of 638787241 is about 25274.2406611949. The cubic root of 638787241 is about 861.2291963942.

The spelling of 638787241 in words is "six hundred thirty-eight million, seven hundred eighty-seven thousand, two hundred forty-one".