128577780 has 120 divisors (see below), whose sum is σ = 406966560. Its totient is φ = 33981120.

The previous prime is 128577767. The next prime is 128577781. The reversal of 128577780 is 87775821.

128577780 is a `hidden beast` number, since 1 + 2 + 8 + 577 + 78 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128577781) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 224895 + ... + 225465.

It is an arithmetic number, because the mean of its divisors is an integer number (3391388).

Almost surely, 2^128577780 is an apocalyptic number.

128577780 is a gapful number since it is divisible by the number (10) 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 128577780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (203483280).

128577780 is an abundant number, since it is smaller than the sum of its proper divisors (278388780).

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

128577780 is a wasteful number, since it uses less digits than its factorization.

128577780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731 (or 720 counting only the distinct ones).

The product of its (nonzero) digits is 219520, while the sum is 45.

The square root of 128577780 is about 11339.2142584925. The cubic root of 128577780 is about 504.7255705960.

The spelling of 128577780 in words is "one hundred twenty-eight million, five hundred seventy-seven thousand, seven hundred eighty".