128417681 has 12 divisors (see below), whose sum is σ = 149579172. Its totient is φ = 109928448.

The previous prime is 128417659. The next prime is 128417687. The reversal of 128417681 is 186714821.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 108347281 + 20070400 = 10409^2 + 4480^2 .

It is a de Polignac number, because none of the positive numbers 2^k-128417681 is a prime.

It is a super-2 number, since 2×128417681² = 32982201586835522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128417687) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55361 + ... + 57633.

It is an arithmetic number, because the mean of its divisors is an integer number (12464931).

Almost surely, 2^128417681 is an apocalyptic number.

It is an amenable number.

128417681 is a deficient number, since it is larger than the sum of its proper divisors (21161491).

128417681 is a wasteful number, since it uses less digits than its factorization.

128417681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3440 (or 3433 counting only the distinct ones).

The product of its digits is 21504, while the sum is 38.

The square root of 128417681 is about 11332.1525316243. The cubic root of 128417681 is about 504.5159967464.

The spelling of 128417681 in words is "one hundred twenty-eight million, four hundred seventeen thousand, six hundred eighty-one".