128617889399 has 4 divisors (see below), whose sum is σ = 130429409040. Its totient is φ = 126806369760.

The previous prime is 128617889369. The next prime is 128617889437. The reversal of 128617889399 is 993988716821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 993988716821 = 21157 ⋅46981553.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128617889399 is a prime.

It is a super-2 number, since 2×128617889399² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (71), and also a Moran number because the ratio is a prime number: 1811519569 = 128617889399 / (1 + 2 + 8 + 6 + 1 + 7 + 8 + 8 + 9 + 3 + 9 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128617889369) 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, 905759714 + ... + 905759855.

It is an arithmetic number, because the mean of its divisors is an integer number (32607352260).

Almost surely, 2^128617889399 is an apocalyptic number.

128617889399 is a deficient number, since it is larger than the sum of its proper divisors (1811519641).

128617889399 is an equidigital number, since it uses as much as digits as its factorization.

128617889399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1811519640.

The product of its digits is 94058496, while the sum is 71.

The spelling of 128617889399 in words is "one hundred twenty-eight billion, six hundred seventeen million, eight hundred eighty-nine thousand, three hundred ninety-nine".