28028720 has 40 divisors (see below), whose sum is σ = 68004576. Its totient is φ = 10723328.

The previous prime is 28028701. The next prime is 28028723. The reversal of 28028720 is 2782082.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (28028723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5777 + ... + 9456.

Almost surely, 2^28028720 is an apocalyptic number.

28028720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28028720 is an abundant number, since it is smaller than the sum of its proper divisors (39975856).

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

28028720 is a wasteful number, since it uses less digits than its factorization.

28028720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15269 (or 15263 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 28028720 is about 5294.2157115101. The cubic root of 28028720 is about 303.7626841333.

The spelling of 28028720 in words is "twenty-eight million, twenty-eight thousand, seven hundred twenty".