28193920 has 32 divisors (see below), whose sum is σ = 67402620. Its totient is φ = 11277312.

The previous prime is 28193857. The next prime is 28193927. The reversal of 28193920 is 2939182.

It can be written as a sum of positive squares in 2 ways, for example, as 28132416 + 61504 = 5304^2 + 248^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (28193927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21387 + ... + 22666.

Almost surely, 2^28193920 is an apocalyptic number.

28193920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28193920 is an abundant number, since it is smaller than the sum of its proper divisors (39208700).

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

28193920 is an equidigital number, since it uses as much as digits as its factorization.

28193920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44072 (or 44060 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 28193920 is about 5309.7947229625. The cubic root of 28193920 is about 304.3583032891.

The spelling of 28193920 in words is "twenty-eight million, one hundred ninety-three thousand, nine hundred twenty".