128958217 has 8 divisors (see below), whose sum is σ = 134887680. Its totient is φ = 123055680.

The previous prime is 128958197. The next prime is 128958229. The reversal of 128958217 is 712859821.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 128958217 - 2¹⁵ = 128925449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128958017) 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, 3409 + ... + 16417.

It is an arithmetic number, because the mean of its divisors is an integer number (16860960).

Almost surely, 2^128958217 is an apocalyptic number.

It is an amenable number.

128958217 is a deficient number, since it is larger than the sum of its proper divisors (5929463).

128958217 is a wasteful number, since it uses less digits than its factorization.

128958217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13463.

The product of its digits is 80640, while the sum is 43.

The square root of 128958217 is about 11355.9771486209. The cubic root of 128958217 is about 505.2228758401. Note that the first 3 decimals are identical.

It can be divided in two parts, 12895 and 8217, that added together give a palindrome (21112).

The spelling of 128958217 in words is "one hundred twenty-eight million, nine hundred fifty-eight thousand, two hundred seventeen".