28752021 has 12 divisors (see below), whose sum is σ = 42963180. Its totient is φ = 18506880.

The previous prime is 28752019. The next prime is 28752037. The reversal of 28752021 is 12025782.

It can be written as a sum of positive squares in 2 ways, for example, as 5336100 + 23415921 = 2310^2 + 4839^2 .

It is not a de Polignac number, because 28752021 - 2¹ = 28752019 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28752121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54820 + ... + 55341.

It is an arithmetic number, because the mean of its divisors is an integer number (3580265).

Almost surely, 2^28752021 is an apocalyptic number.

It is an amenable number.

28752021 is a deficient number, since it is larger than the sum of its proper divisors (14211159).

28752021 is a wasteful number, since it uses less digits than its factorization.

28752021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110196 (or 110193 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 28752021 is about 5362.0911032917. The cubic root of 28752021 is about 306.3534618638.

The spelling of 28752021 in words is "twenty-eight million, seven hundred fifty-two thousand, twenty-one".