28187540 has 24 divisors (see below), whose sum is σ = 59294592. Its totient is φ = 11255840.

The previous prime is 28187539. The next prime is 28187543. The reversal of 28187540 is 4578182.

It is a super-2 number, since 2×28187540² = 1589074822503200, 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 28187540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28187543) by changing a digit.

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, 19937 + ... + 21303.

It is an arithmetic number, because the mean of its divisors is an integer number (2470608).

Almost surely, 2^28187540 is an apocalyptic number.

28187540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28187540 is an abundant number, since it is smaller than the sum of its proper divisors (31107052).

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

28187540 is a wasteful number, since it uses less digits than its factorization.

28187540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2407 (or 2405 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 28187540 is about 5309.1939124504. The cubic root of 28187540 is about 304.3353438181.

The spelling of 28187540 in words is "twenty-eight million, one hundred eighty-seven thousand, five hundred forty".