138221129 has 4 divisors (see below), whose sum is σ = 140563920. Its totient is φ = 135878340.

The previous prime is 138221123. The next prime is 138221137. The reversal of 138221129 is 921122831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138221129 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138221123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1171307 + ... + 1171424.

It is an arithmetic number, because the mean of its divisors is an integer number (35140980).

Almost surely, 2^138221129 is an apocalyptic number.

It is an amenable number.

138221129 is a deficient number, since it is larger than the sum of its proper divisors (2342791).

138221129 is an equidigital number, since it uses as much as digits as its factorization.

138221129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2342790.

The product of its digits is 1728, while the sum is 29.

The square root of 138221129 is about 11756.7482323983. The cubic root of 138221129 is about 517.0407965642.

The spelling of 138221129 in words is "one hundred thirty-eight million, two hundred twenty-one thousand, one hundred twenty-nine".