138691765 has 8 divisors (see below), whose sum is σ = 167024088. Its totient is φ = 110557440.

The previous prime is 138691757. The next prime is 138691769. The reversal of 138691765 is 567196831.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 55681444 + 83010321 = 7462^2 + 9111^2 .

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

It is not a de Polignac number, because 138691765 - 2³ = 138691757 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 (138691769) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47952 + ... + 50761.

It is an arithmetic number, because the mean of its divisors is an integer number (20878011).

Almost surely, 2^138691765 is an apocalyptic number.

It is an amenable number.

138691765 is a deficient number, since it is larger than the sum of its proper divisors (28332323).

138691765 is an equidigital number, since it uses as much as digits as its factorization.

138691765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98999.

The product of its digits is 272160, while the sum is 46.

The square root of 138691765 is about 11776.7467918776. The cubic root of 138691765 is about 517.6269644214.

The spelling of 138691765 in words is "one hundred thirty-eight million, six hundred ninety-one thousand, seven hundred sixty-five".