138231668 has 6 divisors (see below), whose sum is σ = 241905426. Its totient is φ = 69115832.

The previous prime is 138231649. The next prime is 138231739. The reversal of 138231668 is 866132831.

It can be written as a sum of positive squares in only one way, i.e., 77827684 + 60403984 = 8822^2 + 7772^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17278955 + ... + 17278962.

It is an arithmetic number, because the mean of its divisors is an integer number (40317571).

Almost surely, 2^138231668 is an apocalyptic number.

It is an amenable number.

138231668 is a deficient number, since it is larger than the sum of its proper divisors (103673758).

138231668 is a wasteful number, since it uses less digits than its factorization.

138231668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34557921 (or 34557919 counting only the distinct ones).

The product of its digits is 41472, while the sum is 38.

The square root of 138231668 is about 11757.1964345247. The cubic root of 138231668 is about 517.0539372335.

The spelling of 138231668 in words is "one hundred thirty-eight million, two hundred thirty-one thousand, six hundred sixty-eight".