128890609 has 3 divisors (see below), whose sum is σ = 128901963. Its totient is φ = 128879256.

The previous prime is 128890603. The next prime is 128890613. The reversal of 128890609 is 906098821.

It is a happy number.

The square root of 128890609 is 11353.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 906098821 = 67 ⋅13523863.

It can be written as a sum of positive squares in only one way, i.e., 35343025 + 93547584 = 5945^2 + 9672^2 .

It is not a de Polignac number, because 128890609 - 2¹¹ = 128888561 is a prime.

It is a super-2 number, since 2×128890609² = 33225578176781762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128890603) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 5677 + ... + 17029.

It is an arithmetic number, because the mean of its divisors is an integer number (42967321).

Almost surely, 2^128890609 is an apocalyptic number.

128890609 is the 11353-rd square number.

128890609 is the 5677-th centered octagonal number.

It is an amenable number.

128890609 is a deficient number, since it is larger than the sum of its proper divisors (11354).

128890609 is an frugal number, since it uses more digits than its factorization.

128890609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22706 (or 11353 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 43.

The cubic root of 128890609 is about 505.1345705481.

The spelling of 128890609 in words is "one hundred twenty-eight million, eight hundred ninety thousand, six hundred nine".