28128945 has 32 divisors (see below), whose sum is σ = 49214592. Its totient is φ = 13635072.

The previous prime is 28128941. The next prime is 28128953. The reversal of 28128945 is 54982182.

It is not a de Polignac number, because 28128945 - 2² = 28128941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28128941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11989 + ... + 14141.

It is an arithmetic number, because the mean of its divisors is an integer number (1537956).

Almost surely, 2^28128945 is an apocalyptic number.

It is an amenable number.

28128945 is a deficient number, since it is larger than the sum of its proper divisors (21085647).

28128945 is a wasteful number, since it uses less digits than its factorization.

28128945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2241.

The product of its digits is 46080, while the sum is 39.

The square root of 28128945 is about 5303.6727840243. The cubic root of 28128945 is about 304.1243179506.

The spelling of 28128945 in words is "twenty-eight million, one hundred twenty-eight thousand, nine hundred forty-five".