128725650 has 72 divisors (see below), whose sum is σ = 354328884. Its totient is φ = 33484800.

The previous prime is 128725643. The next prime is 128725651. The reversal of 128725650 is 56527821.

It is a happy number.

128725650 is a `hidden beast` number, since 1 + 28 + 72 + 565 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 5049009 + 123676641 = 2247^2 + 11121^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128725651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 14962 + ... + 21938.

Almost surely, 2^128725650 is an apocalyptic number.

128725650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 128725650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (177164442).

128725650 is an abundant number, since it is smaller than the sum of its proper divisors (225603234).

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

128725650 is a wasteful number, since it uses less digits than its factorization.

128725650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7036 (or 7028 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 128725650 is about 11345.7326779719. The cubic root of 128725650 is about 504.9189818726.

The spelling of 128725650 in words is "one hundred twenty-eight million, seven hundred twenty-five thousand, six hundred fifty".