128445021 has 20 divisors (see below), whose sum is σ = 192956764. Its totient is φ = 85147200.

The previous prime is 128445011. The next prime is 128445029. The reversal of 128445021 is 120544821.

It can be written as a sum of positive squares in 2 ways, for example, as 4901796 + 123543225 = 2214^2 + 11115^2 .

It is not a de Polignac number, because 128445021 - 2⁵ = 128444989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128445029) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10281 + ... + 19041.

Almost surely, 2^128445021 is an apocalyptic number.

It is an amenable number.

128445021 is a deficient number, since it is larger than the sum of its proper divisors (64511743).

128445021 is an equidigital number, since it uses as much as digits as its factorization.

128445021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8954 (or 8945 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 128445021 is about 11333.3587695793. The cubic root of 128445021 is about 504.5517978617.

Adding to 128445021 its reverse (120544821), we get a palindrome (248989842).

The spelling of 128445021 in words is "one hundred twenty-eight million, four hundred forty-five thousand, twenty-one".