20128420 has 24 divisors (see below), whose sum is σ = 45521784. Its totient is φ = 7431936.

The previous prime is 20128411. The next prime is 20128421. The reversal of 20128420 is 2482102.

It can be written as a sum of positive squares in 4 ways, for example, as 272484 + 19855936 = 522^2 + 4456^2 .

It is not an unprimeable number, because it can be changed into a prime (20128421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38449 + ... + 38968.

It is an arithmetic number, because the mean of its divisors is an integer number (1896741).

Almost surely, 2^20128420 is an apocalyptic number.

20128420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20128420 is an abundant number, since it is smaller than the sum of its proper divisors (25393364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20128420 is a wasteful number, since it uses less digits than its factorization.

20128420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77439 (or 77437 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 20128420 is about 4486.4707733362. The cubic root of 20128420 is about 272.0214984449.

The spelling of 20128420 in words is "twenty million, one hundred twenty-eight thousand, four hundred twenty".