28323720 has 96 divisors (see below), whose sum is σ = 95261400. Its totient is φ = 7289856.

The previous prime is 28323689. The next prime is 28323727. The reversal of 28323720 is 2732382.

It can be written as a sum of positive squares in 4 ways, for example, as 27941796 + 381924 = 5286^2 + 618^2 .

It is a super-2 number, since 2×28323720² = 1604466229276800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28323727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9084 + ... + 11796.

Almost surely, 2^28323720 is an apocalyptic number.

28323720 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 28323720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47630700).

28323720 is an abundant number, since it is smaller than the sum of its proper divisors (66937680).

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

28323720 is a wasteful number, since it uses less digits than its factorization.

28323720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2759 (or 2752 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 28323720 is about 5322.0033821861. The cubic root of 28323720 is about 304.8246595875.

The spelling of 28323720 in words is "twenty-eight million, three hundred twenty-three thousand, seven hundred twenty".