128649 has 16 divisors (see below), whose sum is σ = 188480. Its totient is φ = 77760.

The previous prime is 128629. The next prime is 128657. The reversal of 128649 is 946821.

It is not a de Polignac number, because 128649 - 2⁷ = 128521 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

128649 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (128629) 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, 2079 + ... + 2139.

It is an arithmetic number, because the mean of its divisors is an integer number (11780).

2¹²⁸⁶⁴⁹ is an apocalyptic number.

128649 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

128649 is a deficient number, since it is larger than the sum of its proper divisors (59831).

128649 is a wasteful number, since it uses less digits than its factorization.

128649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120.

The product of its digits is 3456, while the sum is 30.

The square root of 128649 is about 358.6767346790. The cubic root of 128649 is about 50.4818743564.

It can be divided in two parts, 128 and 649, that added together give a palindrome (777).

The spelling of 128649 in words is "one hundred twenty-eight thousand, six hundred forty-nine".