138755621454221 has 4 divisors (see below), whose sum is σ = 146058548899200. Its totient is φ = 131452694009244.

The previous prime is 138755621454199. The next prime is 138755621454251. The reversal of 138755621454221 is 122454126557831.

It is a happy number.

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-138755621454221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138755621454251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3651463722461 + ... + 3651463722498.

It is an arithmetic number, because the mean of its divisors is an integer number (36514637224800).

Almost surely, 2^{138755621454221} is an apocalyptic number.

It is an amenable number.

138755621454221 is a deficient number, since it is larger than the sum of its proper divisors (7302927444979).

138755621454221 is an equidigital number, since it uses as much as digits as its factorization.

138755621454221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7302927444978.

The product of its digits is 16128000, while the sum is 56.

The spelling of 138755621454221 in words is "one hundred thirty-eight trillion, seven hundred fifty-five billion, six hundred twenty-one million, four hundred fifty-four thousand, two hundred twenty-one".