138762509 has 4 divisors (see below), whose sum is σ = 138844860. Its totient is φ = 138680160.

The previous prime is 138762499. The next prime is 138762511. The reversal of 138762509 is 905267831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 89832484 + 48930025 = 9478^2 + 6995^2 .

It is a cyclic number.

It is not a de Polignac number, because 138762509 - 2⁴ = 138762493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138762539) 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, 38594 + ... + 42035.

It is an arithmetic number, because the mean of its divisors is an integer number (34711215).

Almost surely, 2^138762509 is an apocalyptic number.

It is an amenable number.

138762509 is a deficient number, since it is larger than the sum of its proper divisors (82351).

138762509 is an equidigital number, since it uses as much as digits as its factorization.

138762509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82350.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 138762509 is about 11779.7499549014. The cubic root of 138762509 is about 517.7149599788.

The spelling of 138762509 in words is "one hundred thirty-eight million, seven hundred sixty-two thousand, five hundred nine".