128321565 has 8 divisors (see below), whose sum is σ = 205314528. Its totient is φ = 68438160.

The previous prime is 128321551. The next prime is 128321597. The reversal of 128321565 is 565123821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128321565 - 2¹⁰ = 128320541 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4277371 + ... + 4277400.

It is an arithmetic number, because the mean of its divisors is an integer number (25664316).

Almost surely, 2^128321565 is an apocalyptic number.

128321565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128321565 is a deficient number, since it is larger than the sum of its proper divisors (76992963).

128321565 is an equidigital number, since it uses as much as digits as its factorization.

128321565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8554779.

The product of its digits is 14400, while the sum is 33.

The square root of 128321565 is about 11327.9108841834. The cubic root of 128321565 is about 504.3900946578.

The spelling of 128321565 in words is "one hundred twenty-eight million, three hundred twenty-one thousand, five hundred sixty-five".