28527921 has 24 divisors (see below), whose sum is σ = 43981704. Its totient is φ = 17756160.

The previous prime is 28527913. The next prime is 28527929. The reversal of 28527921 is 12972582.

It is an interprime number because it is at equal distance from previous prime (28527913) and next prime (28527929).

It can be written as a sum of positive squares in 4 ways, for example, as 4410000 + 24117921 = 2100^2 + 4911^2 .

It is not a de Polignac number, because 28527921 - 2³ = 28527913 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28527929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20281 + ... + 21641.

It is an arithmetic number, because the mean of its divisors is an integer number (1832571).

Almost surely, 2^28527921 is an apocalyptic number.

It is an amenable number.

28527921 is a deficient number, since it is larger than the sum of its proper divisors (15453783).

28527921 is a wasteful number, since it uses less digits than its factorization.

28527921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1521 (or 1518 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 28527921 is about 5341.1535270951. The cubic root of 28527921 is about 305.5554547119. Note that the first 3 decimals are identical.

The spelling of 28527921 in words is "twenty-eight million, five hundred twenty-seven thousand, nine hundred twenty-one".