128440520 has 32 divisors (see below), whose sum is σ = 311222520. Its totient is φ = 47424000.

The previous prime is 128440517. The next prime is 128440531. The reversal of 128440520 is 25044821.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 39967684 + 88472836 = 6322^2 + 9406^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 128440520.

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, 122981 + ... + 124020.

Almost surely, 2^128440520 is an apocalyptic number.

128440520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128440520 is an abundant number, since it is smaller than the sum of its proper divisors (182782000).

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

128440520 is a wasteful number, since it uses less digits than its factorization.

128440520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247025 (or 247021 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 128440520 is about 11333.1601947559. The cubic root of 128440520 is about 504.5459042527.

The spelling of 128440520 in words is "one hundred twenty-eight million, four hundred forty thousand, five hundred twenty".