138000661 has 2 divisors, whose sum is σ = 138000662. Its totient is φ = 138000660.

The previous prime is 138000659. The next prime is 138000673. The reversal of 138000661 is 166000831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137030436 + 970225 = 11706^2 + 985^2 .

It is a cyclic number.

It is not a de Polignac number, because 138000661 - 2¹ = 138000659 is a prime.

Together with 138000659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138000061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69000330 + 69000331.

It is an arithmetic number, because the mean of its divisors is an integer number (69000331).

Almost surely, 2^138000661 is an apocalyptic number.

It is an amenable number.

138000661 is a deficient number, since it is larger than the sum of its proper divisors (1).

138000661 is an equidigital number, since it uses as much as digits as its factorization.

138000661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 138000661 is about 11747.3682584654. The cubic root of 138000661 is about 516.7657503114.

The spelling of 138000661 in words is "one hundred thirty-eight million, six hundred sixty-one", and thus it is an aban number.