28707440 has 40 divisors (see below), whose sum is σ = 67079040. Its totient is φ = 11425536.

The previous prime is 28707433. The next prime is 28707443. The reversal of 28707440 is 4470782.

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

It is a super-2 number, since 2×28707440² = 1648234222707200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28707397 and 28707406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28707443) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 17537 + ... + 19103.

It is an arithmetic number, because the mean of its divisors is an integer number (1676976).

Almost surely, 2^28707440 is an apocalyptic number.

28707440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28707440 is an abundant number, since it is smaller than the sum of its proper divisors (38371600).

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

28707440 is a wasteful number, since it uses less digits than its factorization.

28707440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809 (or 1803 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 32.

The square root of 28707440 is about 5357.9324370507. The cubic root of 28707440 is about 306.1950427554.

The spelling of 28707440 in words is "twenty-eight million, seven hundred seven thousand, four hundred forty".