128787381 has 8 divisors (see below), whose sum is σ = 190796160. Its totient is φ = 85858236.

The previous prime is 128787353. The next prime is 128787391. The reversal of 128787381 is 183787821.

It is not a de Polignac number, because 128787381 - 2⁵ = 128787349 is a prime.

It is a super-2 number, since 2×128787381² = 33172379009678322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128787311) 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, 2384925 + ... + 2384978.

It is an arithmetic number, because the mean of its divisors is an integer number (23849520).

Almost surely, 2^128787381 is an apocalyptic number.

It is an amenable number.

128787381 is a deficient number, since it is larger than the sum of its proper divisors (62008779).

128787381 is an equidigital number, since it uses as much as digits as its factorization.

128787381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4769912 (or 4769906 counting only the distinct ones).

The product of its digits is 150528, while the sum is 45.

The square root of 128787381 is about 11348.4528020343. The cubic root of 128787381 is about 504.9996810768. Note that the first 3 decimals are identical.

The spelling of 128787381 in words is "one hundred twenty-eight million, seven hundred eighty-seven thousand, three hundred eighty-one".