28261644 has 12 divisors (see below), whose sum is σ = 65943864. Its totient is φ = 9420544.

The previous prime is 28261637. The next prime is 28261657. The reversal of 28261644 is 44616282.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1177557 + ... + 1177580.

It is an arithmetic number, because the mean of its divisors is an integer number (5495322).

Almost surely, 2^28261644 is an apocalyptic number.

It is an amenable number.

28261644 is an abundant number, since it is smaller than the sum of its proper divisors (37682220).

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

28261644 is a wasteful number, since it uses less digits than its factorization.

28261644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2355144 (or 2355142 counting only the distinct ones).

The product of its digits is 18432, while the sum is 33.

The square root of 28261644 is about 5316.1681688976. The cubic root of 28261644 is about 304.6018059019.

The spelling of 28261644 in words is "twenty-eight million, two hundred sixty-one thousand, six hundred forty-four".