138219691 has 2 divisors, whose sum is σ = 138219692. Its totient is φ = 138219690.

The previous prime is 138219671. The next prime is 138219703. The reversal of 138219691 is 196912831.

It is a strong prime.

It is an emirp because it is prime and its reverse (196912831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138219691 - 2⁷ = 138219563 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138219671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69109845 + 69109846.

It is an arithmetic number, because the mean of its divisors is an integer number (69109846).

Almost surely, 2^138219691 is an apocalyptic number.

138219691 is a deficient number, since it is larger than the sum of its proper divisors (1).

138219691 is an equidigital number, since it uses as much as digits as its factorization.

138219691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 40.

The square root of 138219691 is about 11756.6870758730. The cubic root of 138219691 is about 517.0390035261.

The spelling of 138219691 in words is "one hundred thirty-eight million, two hundred nineteen thousand, six hundred ninety-one".