138409893 has 12 divisors (see below), whose sum is σ = 200048940. Its totient is φ = 92216256.

The previous prime is 138409879. The next prime is 138409907. The reversal of 138409893 is 398904831.

It is an interprime number because it is at equal distance from previous prime (138409879) and next prime (138409907).

It can be written as a sum of positive squares in 2 ways, for example, as 14265729 + 124144164 = 3777^2 + 11142^2 .

It is not a de Polignac number, because 138409893 - 2²² = 134215589 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138409093) 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, 14905 + ... + 22337.

It is an arithmetic number, because the mean of its divisors is an integer number (16670745).

Almost surely, 2^138409893 is an apocalyptic number.

It is an amenable number.

138409893 is a deficient number, since it is larger than the sum of its proper divisors (61639047).

138409893 is a wasteful number, since it uses less digits than its factorization.

138409893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9508 (or 9505 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 138409893 is about 11764.7733934828. The cubic root of 138409893 is about 517.2760579751.

The spelling of 138409893 in words is "one hundred thirty-eight million, four hundred nine thousand, eight hundred ninety-three".