28539640 has 16 divisors (see below), whose sum is σ = 64214280. Its totient is φ = 11415840.

The previous prime is 28539629. The next prime is 28539647. The reversal of 28539640 is 4693582.

It is a super-2 number, since 2×28539640² = 1629022102659200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28539640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28539647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 356706 + ... + 356785.

Almost surely, 2^28539640 is an apocalyptic number.

28539640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28539640 is an abundant number, since it is smaller than the sum of its proper divisors (35674640).

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

28539640 is a wasteful number, since it uses less digits than its factorization.

28539640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713502 (or 713498 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 28539640 is about 5342.2504621180. The cubic root of 28539640 is about 305.5972887473.

The spelling of 28539640 in words is "twenty-eight million, five hundred thirty-nine thousand, six hundred forty".