128865519 has 8 divisors (see below), whose sum is σ = 190911920. Its totient is φ = 85910328.

The previous prime is 128865469. The next prime is 128865533. The reversal of 128865519 is 915568821.

It is a happy number.

128865519 is a `hidden beast` number, since 12 + 8 + 86 + 551 + 9 = 666.

It is not a de Polignac number, because 128865519 - 2⁹ = 128865007 is a prime.

It is a super-2 number, since 2×128865519² = 33212643974278722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128865719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2386372 + ... + 2386425.

It is an arithmetic number, because the mean of its divisors is an integer number (23863990).

Almost surely, 2^128865519 is an apocalyptic number.

128865519 is a deficient number, since it is larger than the sum of its proper divisors (62046401).

128865519 is an equidigital number, since it uses as much as digits as its factorization.

128865519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4772806 (or 4772800 counting only the distinct ones).

The product of its digits is 172800, while the sum is 45.

The square root of 128865519 is about 11351.8949519452. The cubic root of 128865519 is about 505.1017917213.

The spelling of 128865519 in words is "one hundred twenty-eight million, eight hundred sixty-five thousand, five hundred nineteen".