138693668 has 6 divisors (see below), whose sum is σ = 242713926. Its totient is φ = 69346832.

The previous prime is 138693637. The next prime is 138693683. The reversal of 138693668 is 866396831.

It can be written as a sum of positive squares in only one way, i.e., 72726784 + 65966884 = 8528^2 + 8122^2 .

It is a super-5 number, since 5×138693668⁵ (a number of 42 digits) contains 55555 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 17336705 + ... + 17336712.

It is an arithmetic number, because the mean of its divisors is an integer number (40452321).

Almost surely, 2^138693668 is an apocalyptic number.

It is an amenable number.

138693668 is a deficient number, since it is larger than the sum of its proper divisors (104020258).

138693668 is a wasteful number, since it uses less digits than its factorization.

138693668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34673421 (or 34673419 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 50.

The square root of 138693668 is about 11776.8275864088. The cubic root of 138693668 is about 517.6293318765.

The spelling of 138693668 in words is "one hundred thirty-eight million, six hundred ninety-three thousand, six hundred sixty-eight".