28900640 has 24 divisors (see below), whose sum is σ = 68278140. Its totient is φ = 11560192.

The previous prime is 28900633. The next prime is 28900643. The reversal of 28900640 is 4600982.

It can be written as a sum of positive squares in 2 ways, for example, as 26091664 + 2808976 = 5108^2 + 1676^2 .

It is not an unprimeable number, because it can be changed into a prime (28900643) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 90155 + ... + 90474.

Almost surely, 2^28900640 is an apocalyptic number.

28900640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28900640 is an abundant number, since it is smaller than the sum of its proper divisors (39377500).

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

28900640 is a wasteful number, since it uses less digits than its factorization.

28900640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180644 (or 180636 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 28900640 is about 5375.9315471832. The cubic root of 28900640 is about 306.8804013053.

The spelling of 28900640 in words is "twenty-eight million, nine hundred thousand, six hundred forty".