638678832481 has 2 divisors, whose sum is σ = 638678832482. Its totient is φ = 638678832480.

The previous prime is 638678832461. The next prime is 638678832509. The reversal of 638678832481 is 184238876836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 637123240000 + 1555592481 = 798200^2 + 39441^2 .

It is a cyclic number.

It is not a de Polignac number, because 638678832481 - 2²⁷ = 638544614753 is a prime.

It is a super-2 number, since 2×638678832481² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (638678832461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319339416240 + 319339416241.

It is an arithmetic number, because the mean of its divisors is an integer number (319339416241).

Almost surely, 2^638678832481 is an apocalyptic number.

It is an amenable number.

638678832481 is a deficient number, since it is larger than the sum of its proper divisors (1).

638678832481 is an equidigital number, since it uses as much as digits as its factorization.

638678832481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 74317824, while the sum is 64.

The spelling of 638678832481 in words is "six hundred thirty-eight billion, six hundred seventy-eight million, eight hundred thirty-two thousand, four hundred eighty-one".