28520380 has 48 divisors (see below), whose sum is σ = 69160896. Its totient is φ = 9676800.

The previous prime is 28520363. The next prime is 28520381. The reversal of 28520380 is 8302582.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28520381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13132 + ... + 15148.

It is an arithmetic number, because the mean of its divisors is an integer number (1440852).

Almost surely, 2^28520380 is an apocalyptic number.

28520380 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 28520380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34580448).

28520380 is an abundant number, since it is smaller than the sum of its proper divisors (40640516).

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

28520380 is a wasteful number, since it uses less digits than its factorization.

28520380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2134 (or 2132 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 28520380 is about 5340.4475467886. The cubic root of 28520380 is about 305.5285290819.

It can be divided in two parts, 28520 and 380, that added together give a square (28900 = 170²).

The spelling of 28520380 in words is "twenty-eight million, five hundred twenty thousand, three hundred eighty".