28172644 has 6 divisors (see below), whose sum is σ = 49302134. Its totient is φ = 14086320.

The previous prime is 28172633. The next prime is 28172657. The reversal of 28172644 is 44627182.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 26936100 + 1236544 = 5190^2 + 1112^2 .

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, 3521577 + ... + 3521584.

Almost surely, 2^28172644 is an apocalyptic number.

It is an amenable number.

28172644 is a deficient number, since it is larger than the sum of its proper divisors (21129490).

28172644 is a wasteful number, since it uses less digits than its factorization.

28172644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7043165 (or 7043163 counting only the distinct ones).

The product of its digits is 21504, while the sum is 34.

The square root of 28172644 is about 5307.7908775686. The cubic root of 28172644 is about 304.2817246412.

The spelling of 28172644 in words is "twenty-eight million, one hundred seventy-two thousand, six hundred forty-four".