1281964320 has 480 divisors, whose sum is σ = 5573449728. Its totient is φ = 270231552.

The previous prime is 1281964309. The next prime is 1281964361. The reversal of 1281964320 is 234691821.

1281964320 is a `hidden beast` number, since 1 + 2 + 8 + 1 + 9 + 643 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

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

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1178817 + ... + 1179903.

Almost surely, 2^1281964320 is an apocalyptic number.

1281964320 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 1281964320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2786724864).

1281964320 is an abundant number, since it is smaller than the sum of its proper divisors (4291485408).

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

1281964320 is a wasteful number, since it uses less digits than its factorization.

1281964320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1134 (or 1117 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 1281964320 is about 35804.5293224195. The cubic root of 1281964320 is about 1086.3221778466.

The spelling of 1281964320 in words is "one billion, two hundred eighty-one million, nine hundred sixty-four thousand, three hundred twenty".