28897920 has 192 divisors, whose sum is σ = 103825800. Its totient is φ = 7397376.

The previous prime is 28897919. The next prime is 28897933. The reversal of 28897920 is 2979882.

It can be written as a sum of positive squares in 4 ways, for example, as 27625536 + 1272384 = 5256^2 + 1128^2 .

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 23 ways as a sum of consecutive naturals, for example, 166954 + ... + 167126.

Almost surely, 2^28897920 is an apocalyptic number.

28897920 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 28897920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51912900).

28897920 is an abundant number, since it is smaller than the sum of its proper divisors (74927880).

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

28897920 is a wasteful number, since it uses less digits than its factorization.

28897920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 28897920 is about 5375.6785618190. The cubic root of 28897920 is about 306.8707735960.

The spelling of 28897920 in words is "twenty-eight million, eight hundred ninety-seven thousand, nine hundred twenty".