138506621 has 16 divisors (see below), whose sum is σ = 160040448. Its totient is φ = 118628400.

The previous prime is 138506611. The next prime is 138506629. The reversal of 138506621 is 126605831.

It is a happy number.

It is not a de Polignac number, because 138506621 - 2²⁶ = 71397757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138506629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12866 + ... + 21036.

It is an arithmetic number, because the mean of its divisors is an integer number (10002528).

Almost surely, 2^138506621 is an apocalyptic number.

138506621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138506621 is a deficient number, since it is larger than the sum of its proper divisors (21533827).

138506621 is a wasteful number, since it uses less digits than its factorization.

138506621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8272.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 138506621 is about 11768.8835919130. The cubic root of 138506621 is about 517.3965296800.

The spelling of 138506621 in words is "one hundred thirty-eight million, five hundred six thousand, six hundred twenty-one".