128003865 has 32 divisors (see below), whose sum is σ = 225666432. Its totient is φ = 61440000.

The previous prime is 128003797. The next prime is 128003879. The reversal of 128003865 is 568300821.

It is a happy number.

It is not a de Polignac number, because 128003865 - 2¹¹ = 128001817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12825 + ... + 20505.

It is an arithmetic number, because the mean of its divisors is an integer number (7052076).

Almost surely, 2^128003865 is an apocalyptic number.

128003865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128003865 is a deficient number, since it is larger than the sum of its proper divisors (97662567).

128003865 is a wasteful number, since it uses less digits than its factorization.

128003865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7801.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 128003865 is about 11313.8793081772. The cubic root of 128003865 is about 503.9734924015.

The spelling of 128003865 in words is "one hundred twenty-eight million, three thousand, eight hundred sixty-five".