638680691249 has 2 divisors, whose sum is σ = 638680691250. Its totient is φ = 638680691248.

The previous prime is 638680691197. The next prime is 638680691281. The reversal of 638680691249 is 942196086836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 594490345024 + 44190346225 = 771032^2 + 210215^2 .

It is a cyclic number.

It is not a de Polignac number, because 638680691249 - 2¹² = 638680687153 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638680691191 and 638680691200.

It is not a weakly prime, because it can be changed into another prime (638680591249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319340345624 + 319340345625.

It is an arithmetic number, because the mean of its divisors is an integer number (319340345625).

Almost surely, 2^638680691249 is an apocalyptic number.

It is an amenable number.

638680691249 is a deficient number, since it is larger than the sum of its proper divisors (1).

638680691249 is an equidigital number, since it uses as much as digits as its factorization.

638680691249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26873856, while the sum is 62.

The spelling of 638680691249 in words is "six hundred thirty-eight billion, six hundred eighty million, six hundred ninety-one thousand, two hundred forty-nine".