28020240 has 60 divisors (see below), whose sum is σ = 94103724. Its totient is φ = 7471872.

The previous prime is 28020229. The next prime is 28020241. The reversal of 28020240 is 4202082.

It can be written as a sum of positive squares in 2 ways, for example, as 6230016 + 21790224 = 2496^2 + 4668^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (28020241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18739 + ... + 20178.

Almost surely, 2^28020240 is an apocalyptic number.

28020240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28020240 is an abundant number, since it is smaller than the sum of its proper divisors (66083484).

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

28020240 is a wasteful number, since it uses less digits than its factorization.

28020240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38936 (or 38927 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 28020240 is about 5293.4147768714. The cubic root of 28020240 is about 303.7320468991.

The spelling of 28020240 in words is "twenty-eight million, twenty thousand, two hundred forty".