138808066 has 4 divisors (see below), whose sum is σ = 208212102. Its totient is φ = 69404032.

The previous prime is 138808063. The next prime is 138808069. The reversal of 138808066 is 660808831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 660808831 = 727 ⋅908953.

It is an interprime number because it is at equal distance from previous prime (138808063) and next prime (138808069).

It can be written as a sum of positive squares in only one way, i.e., 137945025 + 863041 = 11745^2 + 929^2 .

It is not an unprimeable number, because it can be changed into a prime (138808063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34702015 + ... + 34702018.

Almost surely, 2^138808066 is an apocalyptic number.

138808066 is a deficient number, since it is larger than the sum of its proper divisors (69404036).

138808066 is an equidigital number, since it uses as much as digits as its factorization.

138808066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69404035.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 138808066 is about 11781.6834960034. The cubic root of 138808066 is about 517.7716106307.

The spelling of 138808066 in words is "one hundred thirty-eight million, eight hundred eight thousand, sixty-six".