28197920 has 24 divisors (see below), whose sum is σ = 66617964. Its totient is φ = 11279104.

The previous prime is 28197913. The next prime is 28197943. The reversal of 28197920 is 2979182.

It can be written as a sum of positive squares in 2 ways, for example, as 26337424 + 1860496 = 5132^2 + 1364^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87959 + ... + 88278.

Almost surely, 2^28197920 is an apocalyptic number.

28197920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28197920 is an abundant number, since it is smaller than the sum of its proper divisors (38420044).

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

28197920 is a wasteful number, since it uses less digits than its factorization.

28197920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176252 (or 176244 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 28197920 is about 5310.1713719992. The cubic root of 28197920 is about 304.3726961753.

The spelling of 28197920 in words is "twenty-eight million, one hundred ninety-seven thousand, nine hundred twenty".