638005000981 has 16 divisors (see below), whose sum is σ = 641360797168. Its totient is φ = 634661568000.

The previous prime is 638005000957. The next prime is 638005000991. The reversal of 638005000981 is 189000500836.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10726744900 + 627278256081 = 103570^2 + 792009^2 .

It is a cyclic number.

It is not a de Polignac number, because 638005000981 - 2⁵ = 638005000949 is a prime.

It is a super-2 number, since 2×638005000981² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638005000991) 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 in 15 ways as a sum of consecutive naturals, for example, 238327015 + ... + 238329691.

It is an arithmetic number, because the mean of its divisors is an integer number (40085049823).

Almost surely, 2^638005000981 is an apocalyptic number.

It is an amenable number.

638005000981 is a deficient number, since it is larger than the sum of its proper divisors (3355796187).

638005000981 is a wasteful number, since it uses less digits than its factorization.

638005000981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4552.

The product of its (nonzero) digits is 51840, while the sum is 40.

The spelling of 638005000981 in words is "six hundred thirty-eight billion, five million, nine hundred eighty-one", and thus it is an aban number.