138640867 has 2 divisors, whose sum is σ = 138640868. Its totient is φ = 138640866.

The previous prime is 138640841. The next prime is 138640871. The reversal of 138640867 is 768046831.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138640867 is a prime.

It is not a weakly prime, because it can be changed into another prime (138640367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69320433 + 69320434.

It is an arithmetic number, because the mean of its divisors is an integer number (69320434).

Almost surely, 2^138640867 is an apocalyptic number.

138640867 is a deficient number, since it is larger than the sum of its proper divisors (1).

138640867 is an equidigital number, since it uses as much as digits as its factorization.

138640867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 43.

The square root of 138640867 is about 11774.5856402678. The cubic root of 138640867 is about 517.5636359779.

The spelling of 138640867 in words is "one hundred thirty-eight million, six hundred forty thousand, eight hundred sixty-seven".