28720547 has 8 divisors (see below), whose sum is σ = 29581632. Its totient is φ = 27864000.

The previous prime is 28720513. The next prime is 28720553. The reversal of 28720547 is 74502782.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28720547 is a prime.

It is a super-3 number, since 3×28720547³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28720507) 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, 15047 + ... + 16847.

It is an arithmetic number, because the mean of its divisors is an integer number (3697704).

Almost surely, 2^28720547 is an apocalyptic number.

28720547 is a deficient number, since it is larger than the sum of its proper divisors (861085).

28720547 is a wasteful number, since it uses less digits than its factorization.

28720547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2269.

The product of its (nonzero) digits is 31360, while the sum is 35.

The square root of 28720547 is about 5359.1554371934. The cubic root of 28720547 is about 306.2416356455.

The spelling of 28720547 in words is "twenty-eight million, seven hundred twenty thousand, five hundred forty-seven".