638863468057 has 2 divisors, whose sum is σ = 638863468058. Its totient is φ = 638863468056.

The previous prime is 638863468037. The next prime is 638863468073. The reversal of 638863468057 is 750864368836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 391611872521 + 247251595536 = 625789^2 + 497244^2 .

It is a cyclic number.

It is not a de Polignac number, because 638863468057 - 2²³ = 638855079449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 638863468057.

It is not a weakly prime, because it can be changed into another prime (638863468037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319431734028 + 319431734029.

It is an arithmetic number, because the mean of its divisors is an integer number (319431734029).

Almost surely, 2^638863468057 is an apocalyptic number.

It is an amenable number.

638863468057 is a deficient number, since it is larger than the sum of its proper divisors (1).

638863468057 is an equidigital number, since it uses as much as digits as its factorization.

638863468057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139345920, while the sum is 64.

The spelling of 638863468057 in words is "six hundred thirty-eight billion, eight hundred sixty-three million, four hundred sixty-eight thousand, fifty-seven".