28821870 has 96 divisors (see below), whose sum is σ = 93450240. Its totient is φ = 5987520.

The previous prime is 28821869. The next prime is 28821883. The reversal of 28821870 is 7812882.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4851 + ... + 9009.

It is an arithmetic number, because the mean of its divisors is an integer number (973440).

Almost surely, 2^28821870 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28821870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46725120).

28821870 is an abundant number, since it is smaller than the sum of its proper divisors (64628370).

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

28821870 is a wasteful number, since it uses less digits than its factorization.

28821870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4190 (or 4187 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 28821870 is about 5368.6003762620. The cubic root of 28821870 is about 306.6013421561.

The spelling of 28821870 in words is "twenty-eight million, eight hundred twenty-one thousand, eight hundred seventy".