128777217 has 8 divisors (see below), whose sum is σ = 175696224. Its totient is φ = 83854848.

The previous prime is 128777203. The next prime is 128777219. The reversal of 128777217 is 712777821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128777217 - 2⁶ = 128777153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128777219) 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, 499008 + ... + 499265.

It is an arithmetic number, because the mean of its divisors is an integer number (21962028).

Almost surely, 2^128777217 is an apocalyptic number.

It is an amenable number.

128777217 is a deficient number, since it is larger than the sum of its proper divisors (46919007).

128777217 is an equidigital number, since it uses as much as digits as its factorization.

128777217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998319.

The product of its digits is 76832, while the sum is 42.

The square root of 128777217 is about 11348.0049788498. The cubic root of 128777217 is about 504.9863957385.

The spelling of 128777217 in words is "one hundred twenty-eight million, seven hundred seventy-seven thousand, two hundred seventeen".