138391693 has 12 divisors (see below), whose sum is σ = 152702620. Its totient is φ = 125326080.

The previous prime is 138391681. The next prime is 138391703. The reversal of 138391693 is 396193831.

It is a happy number.

138391693 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 48483369 + 89908324 = 6963^2 + 9482^2 .

It is not a de Polignac number, because 138391693 - 2⁵ = 138391661 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 (138391633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31453 + ... + 35581.

Almost surely, 2^138391693 is an apocalyptic number.

It is an amenable number.

138391693 is a deficient number, since it is larger than the sum of its proper divisors (14310927).

138391693 is a wasteful number, since it uses less digits than its factorization.

138391693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4428 (or 4417 counting only the distinct ones).

The product of its digits is 104976, while the sum is 43.

The square root of 138391693 is about 11763.9998724923. Note that the first 3 decimals coincide. The cubic root of 138391693 is about 517.2533841698.

The spelling of 138391693 in words is "one hundred thirty-eight million, three hundred ninety-one thousand, six hundred ninety-three".