128491321 has 16 divisors (see below), whose sum is σ = 158129280. Its totient is φ = 101894400.

The previous prime is 128491313. The next prime is 128491331. The reversal of 128491321 is 123194821.

It is a cyclic number.

It is not a de Polignac number, because 128491321 - 2³ = 128491313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128491301) 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, 2130 + ... + 16171.

It is an arithmetic number, because the mean of its divisors is an integer number (9883080).

Almost surely, 2^128491321 is an apocalyptic number.

It is an amenable number.

128491321 is a deficient number, since it is larger than the sum of its proper divisors (29637959).

128491321 is a wasteful number, since it uses less digits than its factorization.

128491321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18384.

The product of its digits is 3456, while the sum is 31.

The square root of 128491321 is about 11335.4012280113. The cubic root of 128491321 is about 504.6124150858.

The spelling of 128491321 in words is "one hundred twenty-eight million, four hundred ninety-one thousand, three hundred twenty-one".