138723197 has 4 divisors (see below), whose sum is σ = 140096796. Its totient is φ = 137349600.

The previous prime is 138723163. The next prime is 138723217. The reversal of 138723197 is 791327831.

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 123520996 + 15202201 = 11114^2 + 3899^2 .

It is a cyclic number.

It is not a de Polignac number, because 138723197 - 2¹⁸ = 138461053 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 (138723127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 686648 + ... + 686849.

It is an arithmetic number, because the mean of its divisors is an integer number (35024199).

Almost surely, 2^138723197 is an apocalyptic number.

It is an amenable number.

138723197 is a deficient number, since it is larger than the sum of its proper divisors (1373599).

138723197 is a wasteful number, since it uses less digits than its factorization.

138723197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1373598.

The product of its digits is 63504, while the sum is 41.

The square root of 138723197 is about 11778.0812104519. The cubic root of 138723197 is about 517.6660650889. Note that the first 3 decimals are identical.

The spelling of 138723197 in words is "one hundred thirty-eight million, seven hundred twenty-three thousand, one hundred ninety-seven".