128787881 has 4 divisors (see below), whose sum is σ = 131782992. Its totient is φ = 125792772.

The previous prime is 128787877. The next prime is 128787887. The reversal of 128787881 is 188787821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128787881 - 2² = 128787877 is a prime.

It is a super-2 number, since 2×128787881² = 33172636584940322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128787887) 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, 1497491 + ... + 1497576.

It is an arithmetic number, because the mean of its divisors is an integer number (32945748).

Almost surely, 2^128787881 is an apocalyptic number.

It is an amenable number.

128787881 is a deficient number, since it is larger than the sum of its proper divisors (2995111).

128787881 is an equidigital number, since it uses as much as digits as its factorization.

128787881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2995110.

The product of its digits is 401408, while the sum is 50.

The square root of 128787881 is about 11348.4748314476. The cubic root of 128787881 is about 505.0003346075. Note that the first 3 decimals are identical.

The spelling of 128787881 in words is "one hundred twenty-eight million, seven hundred eighty-seven thousand, eight hundred eighty-one".