28578521 has 2 divisors, whose sum is σ = 28578522. Its totient is φ = 28578520.

The previous prime is 28578509. The next prime is 28578533. The reversal of 28578521 is 12587582.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (28578509) and next prime (28578533).

It can be written as a sum of positive squares in only one way, i.e., 28472896 + 105625 = 5336^2 + 325^2 .

It is a cyclic number.

It is not a de Polignac number, because 28578521 - 2⁶ = 28578457 is a prime.

It is not a weakly prime, because it can be changed into another prime (28578421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14289260 + 14289261.

It is an arithmetic number, because the mean of its divisors is an integer number (14289261).

Almost surely, 2^28578521 is an apocalyptic number.

It is an amenable number.

28578521 is a deficient number, since it is larger than the sum of its proper divisors (1).

28578521 is an equidigital number, since it uses as much as digits as its factorization.

28578521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 44800, while the sum is 38.

The square root of 28578521 is about 5345.8882330255. Note that the first 3 decimals coincide. The cubic root of 28578521 is about 305.7360026726.

The spelling of 28578521 in words is "twenty-eight million, five hundred seventy-eight thousand, five hundred twenty-one".