28261620 has 72 divisors (see below), whose sum is σ = 86270184. Its totient is φ = 7488768.

The previous prime is 28261603. The next prime is 28261627. The reversal of 28261620 is 2616282.

28261620 is a `hidden beast` number, since 28 + 2 + 616 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9960336 + 18301284 = 3156^2 + 4278^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28261627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35062 + ... + 35858.

It is an arithmetic number, because the mean of its divisors is an integer number (1198197).

Almost surely, 2^28261620 is an apocalyptic number.

28261620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28261620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43135092).

28261620 is an abundant number, since it is smaller than the sum of its proper divisors (58008564).

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

28261620 is a wasteful number, since it uses less digits than its factorization.

28261620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009 (or 1004 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28261620 is about 5316.1659116322. The cubic root of 28261620 is about 304.6017196785.

The spelling of 28261620 in words is "twenty-eight million, two hundred sixty-one thousand, six hundred twenty".