128676781 has 4 divisors (see below), whose sum is σ = 129690112. Its totient is φ = 127663452.

The previous prime is 128676773. The next prime is 128676841. The reversal of 128676781 is 187676821.

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 128676781 - 2³ = 128676773 is a prime.

It is a super-2 number, since 2×128676781² = 33115427937043922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128676731) 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, 506475 + ... + 506728.

It is an arithmetic number, because the mean of its divisors is an integer number (32422528).

Almost surely, 2^128676781 is an apocalyptic number.

It is an amenable number.

128676781 is a deficient number, since it is larger than the sum of its proper divisors (1013331).

128676781 is a wasteful number, since it uses less digits than its factorization.

128676781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1013330.

The product of its digits is 225792, while the sum is 46.

The square root of 128676781 is about 11343.5788444388. The cubic root of 128676781 is about 504.8550785016.

The spelling of 128676781 in words is "one hundred twenty-eight million, six hundred seventy-six thousand, seven hundred eighty-one".