28639764 has 96 divisors (see below), whose sum is σ = 82857600. Its totient is φ = 8501760.

The previous prime is 28639759. The next prime is 28639777. The reversal of 28639764 is 46793682.

28639764 is a `hidden beast` number, since 2 + 8 + 639 + 7 + 6 + 4 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34474 + ... + 35294.

It is an arithmetic number, because the mean of its divisors is an integer number (863100).

Almost surely, 2^28639764 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28639764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41428800).

28639764 is an abundant number, since it is smaller than the sum of its proper divisors (54217836).

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

28639764 is a wasteful number, since it uses less digits than its factorization.

28639764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870 (or 862 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The square root of 28639764 is about 5351.6132147232. The cubic root of 28639764 is about 305.9542415237.

It can be divided in two parts, 28639 and 764, that added together give a triangular number (29403 = T₂₄₂).

The spelling of 28639764 in words is "twenty-eight million, six hundred thirty-nine thousand, seven hundred sixty-four".