128499217 has 18 divisors (see below), whose sum is σ = 164310594. Its totient is φ = 100124640.

The previous prime is 128499167. The next prime is 128499221. The reversal of 128499217 is 712994821.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 128119761 + 379456 = 11319^2 + 616^2 .

It is a de Polignac number, because none of the positive numbers 2^k-128499217 is a prime.

It is a super-2 number, since 2×128499217² = 33024097539226178, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128499017) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4908 + ... + 16765.

Almost surely, 2^128499217 is an apocalyptic number.

It is an amenable number.

128499217 is a deficient number, since it is larger than the sum of its proper divisors (35811377).

128499217 is a wasteful number, since it uses less digits than its factorization.

128499217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21709 (or 21691 counting only the distinct ones).

The product of its digits is 72576, while the sum is 43.

The square root of 128499217 is about 11335.7495120526. The cubic root of 128499217 is about 504.6227512911.

The spelling of 128499217 in words is "one hundred twenty-eight million, four hundred ninety-nine thousand, two hundred seventeen".