1281335328 has 384 divisors, whose sum is σ = 4719052800. Its totient is φ = 329204736.

The previous prime is 1281335303. The next prime is 1281335353. The reversal of 1281335328 is 8235331821.

It is a happy number.

1281335328 is a `hidden beast` number, since 1 + 281 + 3 + 353 + 28 = 666.

It is an interprime number because it is at equal distance from previous prime (1281335303) and next prime (1281335353).

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

It is a junction number, because it is equal to n+sod(n) for n = 1281335292 and 1281335301.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3380643 + ... + 3381021.

It is an arithmetic number, because the mean of its divisors is an integer number (12289200).

Almost surely, 2^1281335328 is an apocalyptic number.

1281335328 is a gapful number since it is divisible by the number (18) 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 1281335328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359526400).

1281335328 is an abundant number, since it is smaller than the sum of its proper divisors (3437717472).

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

1281335328 is a wasteful number, since it uses less digits than its factorization.

1281335328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461 (or 447 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 1281335328 is about 35795.7445515525. The cubic root of 1281335328 is about 1086.1444818608.

The spelling of 1281335328 in words is "one billion, two hundred eighty-one million, three hundred thirty-five thousand, three hundred twenty-eight".