128085421 has 4 divisors (see below), whose sum is σ = 130185244. Its totient is φ = 125985600.

The previous prime is 128085407. The next prime is 128085437. The reversal of 128085421 is 124580821.

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 24147396 + 103938025 = 4914^2 + 10195^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128085421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128085121) 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, 1049820 + ... + 1049941.

It is an arithmetic number, because the mean of its divisors is an integer number (32546311).

Almost surely, 2^128085421 is an apocalyptic number.

It is an amenable number.

128085421 is a deficient number, since it is larger than the sum of its proper divisors (2099823).

128085421 is an equidigital number, since it uses as much as digits as its factorization.

128085421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2099822.

The product of its (nonzero) digits is 5120, while the sum is 31.

The square root of 128085421 is about 11317.4829798856. The cubic root of 128085421 is about 504.0805030662.

The spelling of 128085421 in words is "one hundred twenty-eight million, eighty-five thousand, four hundred twenty-one".