1281204864 has 192 divisors, whose sum is σ = 4049922240. Its totient is φ = 401780736.

The previous prime is 1281204863. The next prime is 1281204877. The reversal of 1281204864 is 4684021821.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281204863) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 527557 + ... + 529979.

It is an arithmetic number, because the mean of its divisors is an integer number (21093345).

Almost surely, 2^1281204864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1281204864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2024961120).

1281204864 is an abundant number, since it is smaller than the sum of its proper divisors (2768717376).

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

1281204864 is an equidigital number, since it uses as much as digits as its factorization.

1281204864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2469 (or 2445 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 1281204864 is about 35793.9221656415. The cubic root of 1281204864 is about 1086.1076173076.

The spelling of 1281204864 in words is "one billion, two hundred eighty-one million, two hundred four thousand, eight hundred sixty-four".