128861887 has 16 divisors (see below), whose sum is σ = 170111232. Its totient is φ = 94504320.

The previous prime is 128861849. The next prime is 128861891. The reversal of 128861887 is 788168821.

It is a cyclic number.

It is not a de Polignac number, because 128861887 - 2¹⁵ = 128829119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128861887.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128861897) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47913 + ... + 50530.

It is an arithmetic number, because the mean of its divisors is an integer number (10631952).

Almost surely, 2^128861887 is an apocalyptic number.

128861887 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

128861887 is a deficient number, since it is larger than the sum of its proper divisors (41249345).

128861887 is a wasteful number, since it uses less digits than its factorization.

128861887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98478.

The product of its digits is 344064, while the sum is 49.

The square root of 128861887 is about 11351.7349775266. The cubic root of 128861887 is about 505.0970463429.

The spelling of 128861887 in words is "one hundred twenty-eight million, eight hundred sixty-one thousand, eight hundred eighty-seven".