138666540 has 48 divisors (see below), whose sum is σ = 405151488. Its totient is φ = 35369664.

The previous prime is 138666499. The next prime is 138666547. The reversal of 138666540 is 45666831.

It is not an unprimeable number, because it can be changed into a prime (138666547) 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, 48862 + ... + 51621.

It is an arithmetic number, because the mean of its divisors is an integer number (8440656).

Almost surely, 2^138666540 is an apocalyptic number.

138666540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138666540 is an abundant number, since it is smaller than the sum of its proper divisors (266484948).

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

138666540 is a wasteful number, since it uses less digits than its factorization.

138666540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100518 (or 100516 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 39.

The square root of 138666540 is about 11775.6757767867. The cubic root of 138666540 is about 517.5955808424.

The spelling of 138666540 in words is "one hundred thirty-eight million, six hundred sixty-six thousand, five hundred forty".