138221623 has 2 divisors, whose sum is σ = 138221624. Its totient is φ = 138221622.

The previous prime is 138221621. The next prime is 138221641. The reversal of 138221623 is 326122831.

It is a weak prime.

It is an emirp because it is prime and its reverse (326122831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138221623 - 2¹ = 138221621 is a prime.

Together with 138221621, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 138221591 and 138221600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138221621) 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, 69110811 + 69110812.

It is an arithmetic number, because the mean of its divisors is an integer number (69110812).

Almost surely, 2^138221623 is an apocalyptic number.

138221623 is a deficient number, since it is larger than the sum of its proper divisors (1).

138221623 is an equidigital number, since it uses as much as digits as its factorization.

138221623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 28.

The square root of 138221623 is about 11756.7692415901. The cubic root of 138221623 is about 517.0414125285.

It can be divided in two parts, 1382 and 21623, that added together give a triangular number (23005 = T₂₁₄).

The spelling of 138221623 in words is "one hundred thirty-eight million, two hundred twenty-one thousand, six hundred twenty-three".