128642449 has 4 divisors (see below), whose sum is σ = 138538036. Its totient is φ = 118746864.

The previous prime is 128642429. The next prime is 128642453. The reversal of 128642449 is 944246821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 83174400 + 45468049 = 9120^2 + 6743^2 .

It is a cyclic number.

It is not a de Polignac number, because 128642449 - 2¹⁷ = 128511377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128642429) 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, 4947774 + ... + 4947799.

It is an arithmetic number, because the mean of its divisors is an integer number (34634509).

Almost surely, 2^128642449 is an apocalyptic number.

It is an amenable number.

128642449 is a deficient number, since it is larger than the sum of its proper divisors (9895587).

128642449 is an equidigital number, since it uses as much as digits as its factorization.

128642449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9895586.

The product of its digits is 110592, while the sum is 40.

The square root of 128642449 is about 11342.0654644558. The cubic root of 128642449 is about 504.8101747095.

The spelling of 128642449 in words is "one hundred twenty-eight million, six hundred forty-two thousand, four hundred forty-nine".