138561923508 has 24 divisors (see below), whose sum is σ = 333740547840. Its totient is φ = 44697394560.

The previous prime is 138561923501. The next prime is 138561923519. The reversal of 138561923508 is 805329165831.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138561923501) 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, 186238773 + ... + 186239516.

It is an arithmetic number, because the mean of its divisors is an integer number (13905856160).

Almost surely, 2^138561923508 is an apocalyptic number.

It is an amenable number.

138561923508 is an abundant number, since it is smaller than the sum of its proper divisors (195178624332).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138561923508 is a wasteful number, since it uses less digits than its factorization.

138561923508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372478327 (or 372478325 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 51.

The spelling of 138561923508 in words is "one hundred thirty-eight billion, five hundred sixty-one million, nine hundred twenty-three thousand, five hundred eight".