28142640 has 200 divisors, whose sum is σ = 101006928. Its totient is φ = 7257600.

The previous prime is 28142623. The next prime is 28142641. The reversal of 28142640 is 4624182.

28142640 is a `hidden beast` number, since 2 + 8 + 14 + 2 + 640 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28142641) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 278590 + ... + 278690.

Almost surely, 2^28142640 is an apocalyptic number.

28142640 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 28142640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50503464).

28142640 is an abundant number, since it is smaller than the sum of its proper divisors (72864288).

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

28142640 is a wasteful number, since it uses less digits than its factorization.

28142640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 28142640 is about 5304.9637133537. The cubic root of 28142640 is about 304.1736657759.

It can be divided in two parts, 28142 and 640, that added together give a palindrome (28782).

The spelling of 28142640 in words is "twenty-eight million, one hundred forty-two thousand, six hundred forty".