28521644 has 6 divisors (see below), whose sum is σ = 49912884. Its totient is φ = 14260820.

The previous prime is 28521637. The next prime is 28521659. The reversal of 28521644 is 44612582.

It is a self number, because there is not a number n which added to its sum of digits gives 28521644.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 3565202 + ... + 3565209.

It is an arithmetic number, because the mean of its divisors is an integer number (8318814).

Almost surely, 2^28521644 is an apocalyptic number.

It is an amenable number.

28521644 is a deficient number, since it is larger than the sum of its proper divisors (21391240).

28521644 is a wasteful number, since it uses less digits than its factorization.

28521644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7130415 (or 7130413 counting only the distinct ones).

The product of its digits is 15360, while the sum is 32.

The square root of 28521644 is about 5340.5658876190. The cubic root of 28521644 is about 305.5330426070.

The spelling of 28521644 in words is "twenty-eight million, five hundred twenty-one thousand, six hundred forty-four".