128128644 has 72 divisors (see below), whose sum is σ = 372415680. Its totient is φ = 36384192.

The previous prime is 128128639. The next prime is 128128727. The reversal of 128128644 is 446821821.

128128644 is a `hidden beast` number, since 1 + 2 + 8 + 1 + 2 + 8 + 644 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 128128599 and 128128608.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42127 + ... + 45065.

It is an arithmetic number, because the mean of its divisors is an integer number (5172440).

Almost surely, 2^128128644 is an apocalyptic number.

128128644 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128128644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186207840).

128128644 is an abundant number, since it is smaller than the sum of its proper divisors (244287036).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128128644 is a wasteful number, since it uses less digits than its factorization.

128128644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3129 (or 3124 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 128128644 is about 11319.3923865197. The cubic root of 128128644 is about 504.1371980985.

The spelling of 128128644 in words is "one hundred twenty-eight million, one hundred twenty-eight thousand, six hundred forty-four".