28720072 has 16 divisors (see below), whose sum is σ = 57018060. Its totient is φ = 13515264.

The previous prime is 28720037. The next prime is 28720073. The reversal of 28720072 is 27002782.

It can be written as a sum of positive squares in 2 ways, for example, as 28665316 + 54756 = 5354^2 + 234^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28720072.

It is not an unprimeable number, because it can be changed into a prime (28720073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105453 + ... + 105724.

Almost surely, 2^28720072 is an apocalyptic number.

It is an amenable number.

28720072 is a deficient number, since it is larger than the sum of its proper divisors (28297988).

28720072 is a wasteful number, since it uses less digits than its factorization.

28720072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211200 (or 211196 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 28.

The square root of 28720072 is about 5359.1111203258. Note that the first 4 decimals coincide. The cubic root of 28720072 is about 306.2399473585.

The spelling of 28720072 in words is "twenty-eight million, seven hundred twenty thousand, seventy-two".