28311920 has 80 divisors (see below), whose sum is σ = 81036480. Its totient is φ = 8957952.

The previous prime is 28311901. The next prime is 28311947. The reversal of 28311920 is 2911382.

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

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 28311920.

It is a congruent number.

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, 5336 + ... + 9224.

It is an arithmetic number, because the mean of its divisors is an integer number (1012956).

Almost surely, 2^28311920 is an apocalyptic number.

28311920 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 28311920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40518240).

28311920 is an abundant number, since it is smaller than the sum of its proper divisors (52724560).

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

28311920 is a wasteful number, since it uses less digits than its factorization.

28311920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3922 (or 3916 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 28311920 is about 5320.8946616147. The cubic root of 28311920 is about 304.7823225098.

The spelling of 28311920 in words is "twenty-eight million, three hundred eleven thousand, nine hundred twenty".