28961840 has 40 divisors (see below), whose sum is σ = 67779888. Its totient is φ = 11508480.

The previous prime is 28961837. The next prime is 28961879. The reversal of 28961840 is 4816982.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 28961794 and 28961803.

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, 11930 + ... + 14150.

Almost surely, 2^28961840 is an apocalyptic number.

28961840 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 28961840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33889944).

28961840 is an abundant number, since it is smaller than the sum of its proper divisors (38818048).

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

28961840 is a wasteful number, since it uses less digits than its factorization.

28961840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2397 (or 2391 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 28961840 is about 5381.6205737677. The cubic root of 28961840 is about 307.0968652451.

The spelling of 28961840 in words is "twenty-eight million, nine hundred sixty-one thousand, eight hundred forty".