128877281 has 4 divisors (see below), whose sum is σ = 138790932. Its totient is φ = 118963632.

The previous prime is 128877271. The next prime is 128877311. The reversal of 128877281 is 182778821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8755681 + 120121600 = 2959^2 + 10960^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128877281 is a prime.

It is a super-2 number, since 2×128877281² = 33218707115905922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128877241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4956806 + ... + 4956831.

It is an arithmetic number, because the mean of its divisors is an integer number (34697733).

Almost surely, 2^128877281 is an apocalyptic number.

It is an amenable number.

128877281 is a deficient number, since it is larger than the sum of its proper divisors (9913651).

128877281 is an equidigital number, since it uses as much as digits as its factorization.

128877281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9913650.

The product of its digits is 100352, while the sum is 44.

The square root of 128877281 is about 11352.4130034103. The cubic root of 128877281 is about 505.1171587142.

The spelling of 128877281 in words is "one hundred twenty-eight million, eight hundred seventy-seven thousand, two hundred eighty-one".