281228640 has 288 divisors, whose sum is σ = 1125218304. Its totient is φ = 58383360.

The previous prime is 281228617. The next prime is 281228641. The reversal of 281228640 is 46822182.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281228641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 258177 + ... + 259263.

It is an arithmetic number, because the mean of its divisors is an integer number (3907008).

Almost surely, 2^281228640 is an apocalyptic number.

281228640 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 281228640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (562609152).

281228640 is an abundant number, since it is smaller than the sum of its proper divisors (843989664).

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

281228640 is a wasteful number, since it uses less digits than its factorization.

281228640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1130 (or 1115 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 33.

The square root of 281228640 is about 16769.8729869967. The cubic root of 281228640 is about 655.1687617512.

The spelling of 281228640 in words is "two hundred eighty-one million, two hundred twenty-eight thousand, six hundred forty".