138767212521 has 18 divisors (see below), whose sum is σ = 233166677562. Its totient is φ = 79295549760.

The previous prime is 138767212513. The next prime is 138767212547. The reversal of 138767212521 is 125212767831.

138767212521 is a `hidden beast` number, since 1 + 38 + 76 + 7 + 21 + 2 + 521 = 666.

It can be written as a sum of positive squares in only one way, i.e., 96335744400 + 42431468121 = 310380^2 + 205989^2 .

It is not a de Polignac number, because 138767212521 - 2³ = 138767212513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138767212561) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 157332000 + ... + 157332881.

It is an arithmetic number, because the mean of its divisors is an integer number (12953704309).

Almost surely, 2^138767212521 is an apocalyptic number.

It is an amenable number.

138767212521 is a deficient number, since it is larger than the sum of its proper divisors (94399465041).

138767212521 is a wasteful number, since it uses less digits than its factorization.

138767212521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314664901 (or 314664891 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The spelling of 138767212521 in words is "one hundred thirty-eight billion, seven hundred sixty-seven million, two hundred twelve thousand, five hundred twenty-one".