28705620 has 24 divisors (see below), whose sum is σ = 80375904. Its totient is φ = 7654816.

The previous prime is 28705619. The next prime is 28705627. The reversal of 28705620 is 2650782.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28705627) 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, 239154 + ... + 239273.

It is an arithmetic number, because the mean of its divisors is an integer number (3348996).

Almost surely, 2^28705620 is an apocalyptic number.

28705620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28705620 is an abundant number, since it is smaller than the sum of its proper divisors (51670284).

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

28705620 is a wasteful number, since it uses less digits than its factorization.

28705620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478439 (or 478437 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 28705620 is about 5357.7625927247. The cubic root of 28705620 is about 306.1885718805.

The spelling of 28705620 in words is "twenty-eight million, seven hundred five thousand, six hundred twenty".