128781025 has 24 divisors (see below), whose sum is σ = 172399680. Its totient is φ = 95135040.

The previous prime is 128781017. The next prime is 128781047. The reversal of 128781025 is 520187821.

It is not a de Polignac number, because 128781025 - 2³ = 128781017 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12814 + ... + 20536.

It is an arithmetic number, because the mean of its divisors is an integer number (7183320).

Almost surely, 2^128781025 is an apocalyptic number.

It is an amenable number.

128781025 is a deficient number, since it is larger than the sum of its proper divisors (43618655).

128781025 is a wasteful number, since it uses less digits than its factorization.

128781025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7785 (or 7780 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 34.

The square root of 128781025 is about 11348.1727604051. The cubic root of 128781025 is about 504.9913732474.

The spelling of 128781025 in words is "one hundred twenty-eight million, seven hundred eighty-one thousand, twenty-five".