28219920 has 80 divisors (see below), whose sum is σ = 90327552. Its totient is φ = 7280640.

The previous prime is 28219907. The next prime is 28219943. The reversal of 28219920 is 2991282.

It is a happy number.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5544 + ... + 9336.

Almost surely, 2^28219920 is an apocalyptic number.

28219920 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 28219920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45163776).

28219920 is an abundant number, since it is smaller than the sum of its proper divisors (62107632).

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

28219920 is a wasteful number, since it uses less digits than its factorization.

28219920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3840 (or 3834 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 28219920 is about 5312.2424643459. The cubic root of 28219920 is about 304.4518327288.

It can be divided in two parts, 282 and 19920, that added together give a palindrome (20202).

The spelling of 28219920 in words is "twenty-eight million, two hundred nineteen thousand, nine hundred twenty".