128242821 has 8 divisors (see below), whose sum is σ = 195417664. Its totient is φ = 73281600.

The previous prime is 128242819. The next prime is 128242853.

128242821 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128242821 - 2¹ = 128242819 is a prime.

It is a super-2 number, since 2×128242821² = 32892442276076082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128242811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3053380 + ... + 3053421.

It is an arithmetic number, because the mean of its divisors is an integer number (24427208).

Almost surely, 2^128242821 is an apocalyptic number.

It is an amenable number.

128242821 is a deficient number, since it is larger than the sum of its proper divisors (67174843).

128242821 is an equidigital number, since it uses as much as digits as its factorization.

128242821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6106811.

The product of its digits is 4096, while the sum is 30.

The square root of 128242821 is about 11324.4346878774. The cubic root of 128242821 is about 504.2869012453.

The spelling of 128242821 in words is "one hundred twenty-eight million, two hundred forty-two thousand, eight hundred twenty-one".