138255421 has 8 divisors (see below), whose sum is σ = 142232024. Its totient is φ = 134291520.

The previous prime is 138255413. The next prime is 138255431. The reversal of 138255421 is 124552831.

It can be written as a sum of positive squares in 4 ways, for example, as 88623396 + 49632025 = 9414^2 + 7045^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138255421 - 2³ = 138255413 is a prime.

It is a super-2 number, since 2×138255421² = 38229122871774482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138255431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21631 + ... + 27283.

It is an arithmetic number, because the mean of its divisors is an integer number (17779003).

Almost surely, 2^138255421 is an apocalyptic number.

It is an amenable number.

138255421 is a deficient number, since it is larger than the sum of its proper divisors (3976603).

138255421 is an equidigital number, since it uses as much as digits as its factorization.

138255421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6351.

The product of its digits is 9600, while the sum is 31.

The square root of 138255421 is about 11758.2065384139. The cubic root of 138255421 is about 517.0835514769.

The spelling of 138255421 in words is "one hundred thirty-eight million, two hundred fifty-five thousand, four hundred twenty-one".