28159440 has 40 divisors (see below), whose sum is σ = 87295008. Its totient is φ = 7509120.

The previous prime is 28159433. The next prime is 28159441. The reversal of 28159440 is 4495182.

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

It is a super-2 number, since 2×28159440² = 1585908122227200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28159441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58426 + ... + 58905.

Almost surely, 2^28159440 is an apocalyptic number.

28159440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28159440 is an abundant number, since it is smaller than the sum of its proper divisors (59135568).

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

28159440 is a wasteful number, since it uses less digits than its factorization.

28159440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117347 (or 117341 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 28159440 is about 5306.5468998210. The cubic root of 28159440 is about 304.2341801303.

The spelling of 28159440 in words is "twenty-eight million, one hundred fifty-nine thousand, four hundred forty".