138529251 has 16 divisors (see below), whose sum is σ = 234547200. Its totient is φ = 79159464.

The previous prime is 138529249. The next prime is 138529271. The reversal of 138529251 is 152925831.

138529251 is a `hidden beast` number, since 1 + 385 + 29 + 251 = 666.

It is not a de Polignac number, because 138529251 - 2¹ = 138529249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138529271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366291 + ... + 366668.

It is an arithmetic number, because the mean of its divisors is an integer number (14659200).

Almost surely, 2^138529251 is an apocalyptic number.

138529251 is a deficient number, since it is larger than the sum of its proper divisors (96017949).

138529251 is an equidigital number, since it uses as much as digits as its factorization.

138529251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732975 (or 732969 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 138529251 is about 11769.8449862350. The cubic root of 138529251 is about 517.4247065421.

The spelling of 138529251 in words is "one hundred thirty-eight million, five hundred twenty-nine thousand, two hundred fifty-one".