138601665 has 16 divisors (see below), whose sum is σ = 246403200. Its totient is φ = 73920816.

The previous prime is 138601649. The next prime is 138601717. The reversal of 138601665 is 566106831.

It is a happy number.

It is not a de Polignac number, because 138601665 - 2⁴ = 138601649 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 513205 + ... + 513474.

It is an arithmetic number, because the mean of its divisors is an integer number (15400200).

Almost surely, 2^138601665 is an apocalyptic number.

138601665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

138601665 is a deficient number, since it is larger than the sum of its proper divisors (107801535).

138601665 is a wasteful number, since it uses less digits than its factorization.

138601665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026693 (or 1026687 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 138601665 is about 11772.9208355446. The cubic root of 138601665 is about 517.5148493954.

The spelling of 138601665 in words is "one hundred thirty-eight million, six hundred one thousand, six hundred sixty-five".