138404181 has 24 divisors (see below), whose sum is σ = 194056032. Its totient is φ = 87717600.

The previous prime is 138404093. The next prime is 138404207. The reversal of 138404181 is 181404831.

It is not a de Polignac number, because 138404181 - 2⁹ = 138403669 is a prime.

It is a super-2 number, since 2×138404181² = 38311434636561522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138404081) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 175470 + ... + 176256.

It is an arithmetic number, because the mean of its divisors is an integer number (8085668).

Almost surely, 2^138404181 is an apocalyptic number.

It is an amenable number.

138404181 is a deficient number, since it is larger than the sum of its proper divisors (55651851).

138404181 is an equidigital number, since it uses as much as digits as its factorization.

138404181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913 (or 882 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 138404181 is about 11764.5306323712. The cubic root of 138404181 is about 517.2689421025.

The spelling of 138404181 in words is "one hundred thirty-eight million, four hundred four thousand, one hundred eighty-one".