128521139 has 8 divisors (see below), whose sum is σ = 136285920. Its totient is φ = 120779136.

The previous prime is 128521117. The next prime is 128521177. The reversal of 128521139 is 931125821.

It is a happy number.

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 128521139 - 2¹⁶ = 128455603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128521199) 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, 6722 + ... + 17384.

It is an arithmetic number, because the mean of its divisors is an integer number (17035740).

Almost surely, 2^128521139 is an apocalyptic number.

128521139 is a deficient number, since it is larger than the sum of its proper divisors (7764781).

128521139 is a wasteful number, since it uses less digits than its factorization.

128521139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11389.

The product of its digits is 4320, while the sum is 32.

The square root of 128521139 is about 11336.7164117305. The cubic root of 128521139 is about 504.6514459172.

The spelling of 128521139 in words is "one hundred twenty-eight million, five hundred twenty-one thousand, one hundred thirty-nine".