28081644 has 24 divisors (see below), whose sum is σ = 65677248. Its totient is φ = 9338640.

The previous prime is 28081633. The next prime is 28081649. The reversal of 28081644 is 44618082.

It is not an unprimeable number, because it can be changed into a prime (28081649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3099 + ... + 8109.

It is an arithmetic number, because the mean of its divisors is an integer number (2736552).

Almost surely, 2^28081644 is an apocalyptic number.

It is an amenable number.

28081644 is an abundant number, since it is smaller than the sum of its proper divisors (37595604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28081644 is a wasteful number, since it uses less digits than its factorization.

28081644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5485 (or 5483 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 28081644 is about 5299.2116394800. The cubic root of 28081644 is about 303.9537527755.

The spelling of 28081644 in words is "twenty-eight million, eighty-one thousand, six hundred forty-four".