128843781 has 64 divisors (see below), whose sum is σ = 206807040. Its totient is φ = 70560000.

The previous prime is 128843761. The next prime is 128843789. The reversal of 128843781 is 187348821.

It is not a de Polignac number, because 128843781 - 2⁵ = 128843749 is a prime.

It is a super-2 number, since 2×128843781² = 33201439804751922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128843789) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1275631 + ... + 1275731.

It is an arithmetic number, because the mean of its divisors is an integer number (3231360).

Almost surely, 2^128843781 is an apocalyptic number.

128843781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128843781 is a deficient number, since it is larger than the sum of its proper divisors (77963259).

128843781 is a wasteful number, since it uses less digits than its factorization.

128843781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218.

The product of its digits is 86016, while the sum is 42.

The square root of 128843781 is about 11350.9374502726. The cubic root of 128843781 is about 505.0733886743.

The spelling of 128843781 in words is "one hundred twenty-eight million, eight hundred forty-three thousand, seven hundred eighty-one".