28724555 has 4 divisors (see below), whose sum is σ = 34469472. Its totient is φ = 22979640.

The previous prime is 28724503. The next prime is 28724581. The reversal of 28724555 is 55542782.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 28724555 - 2⁶ = 28724491 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2872451 + ... + 2872460.

It is an arithmetic number, because the mean of its divisors is an integer number (8617368).

Almost surely, 2^28724555 is an apocalyptic number.

28724555 is a deficient number, since it is larger than the sum of its proper divisors (5744917).

28724555 is an equidigital number, since it uses as much as digits as its factorization.

28724555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5744916.

The product of its digits is 112000, while the sum is 38.

The square root of 28724555 is about 5359.5293636662. The cubic root of 28724555 is about 306.2558804924.

It can be divided in two parts, 287 and 24555, that added together give a palindrome (24842).

The spelling of 28724555 in words is "twenty-eight million, seven hundred twenty-four thousand, five hundred fifty-five".