28819720 has 32 divisors (see below), whose sum is σ = 66429720. Its totient is φ = 11246080.

The previous prime is 28819711. The next prime is 28819727. The reversal of 28819720 is 2791882.

It can be written as a sum of positive squares in 4 ways, for example, as 18438436 + 10381284 = 4294^2 + 3222^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28819720.

It is not an unprimeable number, because it can be changed into a prime (28819727) 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 7 ways as a sum of consecutive naturals, for example, 7147 + ... + 10426.

Almost surely, 2^28819720 is an apocalyptic number.

28819720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28819720 is an abundant number, since it is smaller than the sum of its proper divisors (37610000).

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

28819720 is a wasteful number, since it uses less digits than its factorization.

28819720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17625 (or 17621 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 28819720 is about 5368.4001341182. The cubic root of 28819720 is about 306.5937182085.

The spelling of 28819720 in words is "twenty-eight million, eight hundred nineteen thousand, seven hundred twenty".