128377640 has 16 divisors (see below), whose sum is σ = 288849780. Its totient is φ = 51351040.

The previous prime is 128377619. The next prime is 128377643. The reversal of 128377640 is 46773821.

It can be written as a sum of positive squares in 2 ways, for example, as 127283524 + 1094116 = 11282^2 + 1046^2 .

It is a junction number, because it is equal to n+sod(n) for n = 128377594 and 128377603.

It is not an unprimeable number, because it can be changed into a prime (128377643) 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, 1604681 + ... + 1604760.

Almost surely, 2^128377640 is an apocalyptic number.

128377640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128377640 is an abundant number, since it is smaller than the sum of its proper divisors (160472140).

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

128377640 is a wasteful number, since it uses less digits than its factorization.

128377640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3209452 (or 3209448 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 38.

The square root of 128377640 is about 11330.3856951121. The cubic root of 128377640 is about 504.4635547856.

The spelling of 128377640 in words is "one hundred twenty-eight million, three hundred seventy-seven thousand, six hundred forty".