28243440 has 60 divisors (see below), whose sum is σ = 94853304. Its totient is φ = 7531392.

The previous prime is 28243433. The next prime is 28243441. The reversal of 28243440 is 4434282.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28243441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18894 + ... + 20333.

Almost surely, 2^28243440 is an apocalyptic number.

28243440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28243440 is an abundant number, since it is smaller than the sum of its proper divisors (66609864).

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

28243440 is a wasteful number, since it uses less digits than its factorization.

28243440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39246 (or 39237 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 27.

The square root of 28243440 is about 5314.4557576482. The cubic root of 28243440 is about 304.5363914218.

The spelling of 28243440 in words is "twenty-eight million, two hundred forty-three thousand, four hundred forty".