28021872 has 20 divisors (see below), whose sum is σ = 72389960. Its totient is φ = 9340608.

The previous prime is 28021841. The next prime is 28021883. The reversal of 28021872 is 27812082.

It is a happy number.

It is a congruent 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, 291847 + ... + 291942.

It is an arithmetic number, because the mean of its divisors is an integer number (3619498).

Almost surely, 2^28021872 is an apocalyptic number.

It is an amenable number.

28021872 is an abundant number, since it is smaller than the sum of its proper divisors (44368088).

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

28021872 is a wasteful number, since it uses less digits than its factorization.

28021872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583800 (or 583794 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 28021872 is about 5293.5689284263. The cubic root of 28021872 is about 303.7379436018.

The spelling of 28021872 in words is "twenty-eight million, twenty-one thousand, eight hundred seventy-two".