138903661 has 16 divisors (see below), whose sum is σ = 161728000. Its totient is φ = 118179648.

The previous prime is 138903643. The next prime is 138903671. The reversal of 138903661 is 166309831.

It is a cyclic number.

It is not a de Polignac number, because 138903661 - 2¹¹ = 138901613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 138903661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138903671) 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, 1540 + ... + 16738.

It is an arithmetic number, because the mean of its divisors is an integer number (10108000).

Almost surely, 2^138903661 is an apocalyptic number.

138903661 is the 6805-th hex number.

It is an amenable number.

138903661 is a deficient number, since it is larger than the sum of its proper divisors (22824339).

138903661 is a wasteful number, since it uses less digits than its factorization.

138903661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15268.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 138903661 is about 11785.7397307085. The cubic root of 138903661 is about 517.8904438283.

The spelling of 138903661 in words is "one hundred thirty-eight million, nine hundred three thousand, six hundred sixty-one".