138551281 has 4 divisors (see below), whose sum is σ = 151146864. Its totient is φ = 125955700.

The previous prime is 138551279. The next prime is 138551291. The reversal of 138551281 is 182155831.

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 not a de Polignac number, because 138551281 - 2¹ = 138551279 is a prime.

It is a super-2 number, since 2×138551281² = 38392914933481922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138551261) 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 in 3 ways as a sum of consecutive naturals, for example, 6297775 + ... + 6297796.

It is an arithmetic number, because the mean of its divisors is an integer number (37786716).

Almost surely, 2^138551281 is an apocalyptic number.

138551281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138551281 is a deficient number, since it is larger than the sum of its proper divisors (12595583).

138551281 is a wasteful number, since it uses less digits than its factorization.

138551281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12595582.

The product of its digits is 9600, while the sum is 34.

The square root of 138551281 is about 11770.7808152221. The cubic root of 138551281 is about 517.4521333900.

The spelling of 138551281 in words is "one hundred thirty-eight million, five hundred fifty-one thousand, two hundred eighty-one".