28528421 has 2 divisors, whose sum is σ = 28528422. Its totient is φ = 28528420.

The previous prime is 28528387. The next prime is 28528427. The reversal of 28528421 is 12482582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16900321 + 11628100 = 4111^2 + 3410^2 .

It is a cyclic number.

It is not a de Polignac number, because 28528421 - 2¹⁰ = 28527397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28528427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14264210 + 14264211.

It is an arithmetic number, because the mean of its divisors is an integer number (14264211).

Almost surely, 2^28528421 is an apocalyptic number.

It is an amenable number.

28528421 is a deficient number, since it is larger than the sum of its proper divisors (1).

28528421 is an equidigital number, since it uses as much as digits as its factorization.

28528421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10240, while the sum is 32.

The square root of 28528421 is about 5341.2003332584. The cubic root of 28528421 is about 305.5572398267.

The spelling of 28528421 in words is "twenty-eight million, five hundred twenty-eight thousand, four hundred twenty-one".