638584701281 has 2 divisors, whose sum is σ = 638584701282. Its totient is φ = 638584701280.

The previous prime is 638584701241. The next prime is 638584701323. The reversal of 638584701281 is 182107485836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 585861653056 + 52723048225 = 765416^2 + 229615^2 .

It is a cyclic number.

It is not a de Polignac number, because 638584701281 - 2⁶ = 638584701217 is a prime.

It is a super-2 number, since 2×638584701281² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (638584701211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319292350640 + 319292350641.

It is an arithmetic number, because the mean of its divisors is an integer number (319292350641).

Almost surely, 2^638584701281 is an apocalyptic number.

It is an amenable number.

638584701281 is a deficient number, since it is larger than the sum of its proper divisors (1).

638584701281 is an equidigital number, since it uses as much as digits as its factorization.

638584701281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2580480, while the sum is 53.

The spelling of 638584701281 in words is "six hundred thirty-eight billion, five hundred eighty-four million, seven hundred one thousand, two hundred eighty-one".