28704540 has 48 divisors (see below), whose sum is σ = 81027072. Its totient is φ = 7592256.

The previous prime is 28704527. The next prime is 28704541. The reversal of 28704540 is 4540782.

28704540 = 411² + 412² + ... + 537².

It is a super-2 number, since 2×28704540² = 1647901233223200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 28704498 and 28704507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28704541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5737 + ... + 9503.

It is an arithmetic number, because the mean of its divisors is an integer number (1688064).

Almost surely, 2^28704540 is an apocalyptic number.

28704540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28704540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40513536).

28704540 is an abundant number, since it is smaller than the sum of its proper divisors (52322532).

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

28704540 is a wasteful number, since it uses less digits than its factorization.

28704540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3906 (or 3904 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 30.

The square root of 28704540 is about 5357.6618034363. The cubic root of 28704540 is about 306.1847318914.

The spelling of 28704540 in words is "twenty-eight million, seven hundred four thousand, five hundred forty".