1281823920 has 320 divisors, whose sum is σ = 4799692800. Its totient is φ = 312560640.

The previous prime is 1281823909. The next prime is 1281823969. The reversal of 1281823920 is 293281821.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 63 ways as a sum of consecutive naturals, for example, 5363161 + ... + 5363399.

It is an arithmetic number, because the mean of its divisors is an integer number (14999040).

Almost surely, 2^1281823920 is an apocalyptic number.

1281823920 is a gapful number since it is divisible by the number (10) 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 1281823920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2399846400).

1281823920 is an abundant number, since it is smaller than the sum of its proper divisors (3517868880).

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

1281823920 is a wasteful number, since it uses less digits than its factorization.

1281823920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465 (or 453 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1281823920 is about 35802.5686229354. The cubic root of 1281823920 is about 1086.2825186040.

The spelling of 1281823920 in words is "one billion, two hundred eighty-one million, eight hundred twenty-three thousand, nine hundred twenty".