138895206521 has 8 divisors (see below), whose sum is σ = 139023000864. Its totient is φ = 138767473600.

The previous prime is 138895206511. The next prime is 138895206533. The reversal of 138895206521 is 125602598831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138895206521 is a prime.

It is a super-3 number, since 3×138895206521³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138895206521.

It is not an unprimeable number, because it can be changed into a prime (138895206511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5328506 + ... + 5354508.

It is an arithmetic number, because the mean of its divisors is an integer number (17377875108).

Almost surely, 2^138895206521 is an apocalyptic number.

It is an amenable number.

138895206521 is a deficient number, since it is larger than the sum of its proper divisors (127794343).

138895206521 is a wasteful number, since it uses less digits than its factorization.

138895206521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30711.

The product of its (nonzero) digits is 1036800, while the sum is 50.

The spelling of 138895206521 in words is "one hundred thirty-eight billion, eight hundred ninety-five million, two hundred six thousand, five hundred twenty-one".