138644887 has 8 divisors (see below), whose sum is σ = 141250880. Its totient is φ = 136049760.

The previous prime is 138644837. The next prime is 138644923. The reversal of 138644887 is 788446831.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138644887 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138644887.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138644837) 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 7 ways as a sum of consecutive naturals, for example, 25789 + ... + 30697.

It is an arithmetic number, because the mean of its divisors is an integer number (17656360).

Almost surely, 2^138644887 is an apocalyptic number.

138644887 is a deficient number, since it is larger than the sum of its proper divisors (2605993).

138644887 is an equidigital number, since it uses as much as digits as its factorization.

138644887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5433.

The product of its digits is 1032192, while the sum is 49.

The square root of 138644887 is about 11774.7563456744. The cubic root of 138644887 is about 517.5686383166.

The spelling of 138644887 in words is "one hundred thirty-eight million, six hundred forty-four thousand, eight hundred eighty-seven".