128310021 has 32 divisors (see below), whose sum is σ = 228684800. Its totient is φ = 69459120.

The previous prime is 128310019. The next prime is 128310037. The reversal of 128310021 is 120013821.

It is not a de Polignac number, because 128310021 - 2¹ = 128310019 is a prime.

It is a super-2 number, since 2×128310021² = 32926922978040882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 128309976 and 128310003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128310521) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14275 + ... + 21456.

It is an arithmetic number, because the mean of its divisors is an integer number (7146400).

Almost surely, 2^128310021 is an apocalyptic number.

It is an amenable number.

128310021 is a deficient number, since it is larger than the sum of its proper divisors (100374779).

128310021 is a wasteful number, since it uses less digits than its factorization.

128310021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35766 (or 35760 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 128310021 is about 11327.4013348164. The cubic root of 128310021 is about 504.3749689750.

Adding to 128310021 its reverse (120013821), we get a palindrome (248323842).

The spelling of 128310021 in words is "one hundred twenty-eight million, three hundred ten thousand, twenty-one".