28199780 has 48 divisors (see below), whose sum is σ = 68656896. Its totient is φ = 9528960.

The previous prime is 28199779. The next prime is 28199789. The reversal of 28199780 is 8799182.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28199789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8522 + ... + 11358.

It is an arithmetic number, because the mean of its divisors is an integer number (1430352).

Almost surely, 2^28199780 is an apocalyptic number.

28199780 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 28199780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34328448).

28199780 is an abundant number, since it is smaller than the sum of its proper divisors (40457116).

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

28199780 is a wasteful number, since it uses less digits than its factorization.

28199780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2924 (or 2922 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 28199780 is about 5310.3465047019. The cubic root of 28199780 is about 304.3793884037.

The spelling of 28199780 in words is "twenty-eight million, one hundred ninety-nine thousand, seven hundred eighty".