138991332909 has 32 divisors (see below), whose sum is σ = 229179686400. Its totient is φ = 73664890560.

The previous prime is 138991332881. The next prime is 138991332923. The reversal of 138991332909 is 909233199831.

It is not a de Polignac number, because 138991332909 - 2¹⁵ = 138991300141 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138991332979) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8517879 + ... + 8534180.

It is an arithmetic number, because the mean of its divisors is an integer number (7161865200).

Almost surely, 2^138991332909 is an apocalyptic number.

138991332909 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

138991332909 is a deficient number, since it is larger than the sum of its proper divisors (90188353491).

138991332909 is a wasteful number, since it uses less digits than its factorization.

138991332909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17052105.

The product of its (nonzero) digits is 2834352, while the sum is 57.

The spelling of 138991332909 in words is "one hundred thirty-eight billion, nine hundred ninety-one million, three hundred thirty-two thousand, nine hundred nine".