138705091 has 16 divisors (see below), whose sum is σ = 171944640. Its totient is φ = 109163520.

The previous prime is 138705089. The next prime is 138705097. The reversal of 138705091 is 190507831.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 138705091 - 2¹ = 138705089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138705097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9336 + ... + 19093.

It is an arithmetic number, because the mean of its divisors is an integer number (10746540).

Almost surely, 2^138705091 is an apocalyptic number.

138705091 is a deficient number, since it is larger than the sum of its proper divisors (33239549).

138705091 is a wasteful number, since it uses less digits than its factorization.

138705091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28494.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 138705091 is about 11777.3125542290. The cubic root of 138705091 is about 517.6435423728.

The spelling of 138705091 in words is "one hundred thirty-eight million, seven hundred five thousand, ninety-one".