138726787 has 4 divisors (see below), whose sum is σ = 138871216. Its totient is φ = 138582360.

The previous prime is 138726761. The next prime is 138726793. The reversal of 138726787 is 787627831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 787627831 = 719 ⋅1095449.

It is a cyclic number.

It is not a de Polignac number, because 138726787 - 2⁷ = 138726659 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 138726787.

It is not an unprimeable number, because it can be changed into a prime (138720787) 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 3 ways as a sum of consecutive naturals, for example, 70764 + ... + 72697.

It is an arithmetic number, because the mean of its divisors is an integer number (34717804).

Almost surely, 2^138726787 is an apocalyptic number.

138726787 is a deficient number, since it is larger than the sum of its proper divisors (144429).

138726787 is an equidigital number, since it uses as much as digits as its factorization.

138726787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144428.

The product of its digits is 790272, while the sum is 49.

The square root of 138726787 is about 11778.2336111999. The cubic root of 138726787 is about 517.6705305885.

The spelling of 138726787 in words is "one hundred thirty-eight million, seven hundred twenty-six thousand, seven hundred eighty-seven".