28403540 has 60 divisors (see below), whose sum is σ = 66288180. Its totient is φ = 10222080.

The previous prime is 28403519. The next prime is 28403561. The reversal of 28403540 is 4530482.

It is an interprime number because it is at equal distance from previous prime (28403519) and next prime (28403561).

It can be written as a sum of positive squares in 2 ways, for example, as 11478544 + 16924996 = 3388^2 + 4114^2 .

It is a super-2 number, since 2×28403540² = 1613522169063200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 292772 + ... + 292868.

It is an arithmetic number, because the mean of its divisors is an integer number (1104803).

Almost surely, 2^28403540 is an apocalyptic number.

28403540 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 28403540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33144090).

28403540 is an abundant number, since it is smaller than the sum of its proper divisors (37884640).

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

28403540 is an equidigital number, since it uses as much as digits as its factorization.

28403540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 28403540 is about 5329.4971620219. The cubic root of 28403540 is about 305.1107364629.

The spelling of 28403540 in words is "twenty-eight million, four hundred three thousand, five hundred forty".