128346640 has 20 divisors (see below), whose sum is σ = 298406124. Its totient is φ = 51338624.

The previous prime is 128346637. The next prime is 128346641. The reversal of 128346640 is 46643821.

It can be written as a sum of positive squares in 2 ways, for example, as 59721984 + 68624656 = 7728^2 + 8284^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 128346596 and 128346605.

It is not an unprimeable number, because it can be changed into a prime (128346641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 802087 + ... + 802246.

Almost surely, 2^128346640 is an apocalyptic number.

128346640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128346640 is an abundant number, since it is smaller than the sum of its proper divisors (170059484).

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

128346640 is a wasteful number, since it uses less digits than its factorization.

128346640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604346 (or 1604340 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 34.

The square root of 128346640 is about 11329.0176096606. The cubic root of 128346640 is about 504.4229463922.

The spelling of 128346640 in words is "one hundred twenty-eight million, three hundred forty-six thousand, six hundred forty".