128381565 has 16 divisors (see below), whose sum is σ = 221211648. Its totient is φ = 63203136.

The previous prime is 128381563. The next prime is 128381587. The reversal of 128381565 is 565183821.

It is not a de Polignac number, because 128381565 - 2¹ = 128381563 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128381563) 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, 328989 + ... + 329378.

It is an arithmetic number, because the mean of its divisors is an integer number (13825728).

Almost surely, 2^128381565 is an apocalyptic number.

128381565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128381565 is a deficient number, since it is larger than the sum of its proper divisors (92830083).

128381565 is a wasteful number, since it uses less digits than its factorization.

128381565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658388.

The product of its digits is 57600, while the sum is 39.

The square root of 128381565 is about 11330.5589006015. The cubic root of 128381565 is about 504.4686958659.

The spelling of 128381565 in words is "one hundred twenty-eight million, three hundred eighty-one thousand, five hundred sixty-five".