28643240 has 32 divisors (see below), whose sum is σ = 65027880. Its totient is φ = 11354112.

The previous prime is 28643239. The next prime is 28643273. The reversal of 28643240 is 4234682.

It can be written as a sum of positive squares in 4 ways, for example, as 12013156 + 16630084 = 3466^2 + 4078^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1352 + ... + 7688.

Almost surely, 2^28643240 is an apocalyptic number.

28643240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28643240 is an abundant number, since it is smaller than the sum of its proper divisors (36384640).

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

28643240 is a wasteful number, since it uses less digits than its factorization.

28643240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6461 (or 6457 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 28643240 is about 5351.9379667556. The cubic root of 28643240 is about 305.9666188827.

The spelling of 28643240 in words is "twenty-eight million, six hundred forty-three thousand, two hundred forty".