138699493 has 4 divisors (see below), whose sum is σ = 139049260. Its totient is φ = 138349728.

The previous prime is 138699443. The next prime is 138699503. The reversal of 138699493 is 394996831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 394996831 = 241 ⋅1638991.

It can be written as a sum of positive squares in 2 ways, for example, as 92486689 + 46212804 = 9617^2 + 6798^2 .

It is a cyclic number.

It is not a de Polignac number, because 138699493 - 2²¹ = 136602341 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 138699493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138699443) 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, 174288 + ... + 175081.

It is an arithmetic number, because the mean of its divisors is an integer number (34762315).

Almost surely, 2^138699493 is an apocalyptic number.

It is an amenable number.

138699493 is a deficient number, since it is larger than the sum of its proper divisors (349767).

138699493 is an equidigital number, since it uses as much as digits as its factorization.

138699493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349766.

The product of its digits is 1259712, while the sum is 52.

The square root of 138699493 is about 11777.0748915000. The cubic root of 138699493 is about 517.6365784190.

The spelling of 138699493 in words is "one hundred thirty-eight million, six hundred ninety-nine thousand, four hundred ninety-three".