28161540 has 144 divisors (see below), whose sum is σ = 96526080. Its totient is φ = 6811200.

The previous prime is 28161509. The next prime is 28161541. The reversal of 28161540 is 4516182.

28161540 is a `hidden beast` number, since 2 + 8 + 1 + 615 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (28161541) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 65125 + ... + 65555.

It is an arithmetic number, because the mean of its divisors is an integer number (670320).

Almost surely, 2^28161540 is an apocalyptic number.

28161540 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 28161540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48263040).

28161540 is an abundant number, since it is smaller than the sum of its proper divisors (68364540).

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

28161540 is a wasteful number, since it uses less digits than its factorization.

28161540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 28161540 is about 5306.7447649195. The cubic root of 28161540 is about 304.2417427322.

It can be divided in two parts, 2816 and 1540, that added together give a square (4356 = 66²).

The spelling of 28161540 in words is "twenty-eight million, one hundred sixty-one thousand, five hundred forty".