28939920 has 80 divisors (see below), whose sum is σ = 92166720. Its totient is φ = 7506432.

The previous prime is 28939877. The next prime is 28939949. The reversal of 28939920 is 2993982.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7251 + ... + 10509.

It is an arithmetic number, because the mean of its divisors is an integer number (1152084).

Almost surely, 2^28939920 is an apocalyptic number.

28939920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28939920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46083360).

28939920 is an abundant number, since it is smaller than the sum of its proper divisors (63226800).

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

28939920 is a wasteful number, since it uses less digits than its factorization.

28939920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3312 (or 3306 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 28939920 is about 5379.5836270106. The cubic root of 28939920 is about 307.0193694520.

The spelling of 28939920 in words is "twenty-eight million, nine hundred thirty-nine thousand, nine hundred twenty".