138721275 has 192 divisors, whose sum is σ = 338549760. Its totient is φ = 53913600.

The previous prime is 138721267. The next prime is 138721301. The reversal of 138721275 is 572127831.

138721275 is a `hidden beast` number, since 1 + 387 + 2 + 1 + 275 = 666.

It is not a de Polignac number, because 138721275 - 2³ = 138721267 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 883497 + ... + 883653.

It is an arithmetic number, because the mean of its divisors is an integer number (1763280).

Almost surely, 2^138721275 is an apocalyptic number.

138721275 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

138721275 is an abundant number, since it is smaller than the sum of its proper divisors (199828485).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138721275 is a wasteful number, since it uses less digits than its factorization.

138721275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 200 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 138721275 is about 11777.9996179317. Note that the first 3 decimals coincide. The cubic root of 138721275 is about 517.6636743358.

The spelling of 138721275 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, two hundred seventy-five".