1281528640 has 112 divisors (see below), whose sum is σ = 3508808832. Its totient is φ = 436709376.

The previous prime is 1281528571. The next prime is 1281528653. The reversal of 1281528640 is 468251821.

It is a tau number, because it is divible by the number of its divisors (112).

It is a self number, because there is not a number n which added to its sum of digits gives 1281528640.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 385867 + ... + 389173.

Almost surely, 2^1281528640 is an apocalyptic number.

1281528640 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 1281528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1754404416).

1281528640 is an abundant number, since it is smaller than the sum of its proper divisors (2227280192).

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

1281528640 is a wasteful number, since it uses less digits than its factorization.

1281528640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3504 (or 3494 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 37.

The square root of 1281528640 is about 35798.4446589513. Note that the first 3 decimals coincide. The cubic root of 1281528640 is about 1086.1991004553.

The spelling of 1281528640 in words is "one billion, two hundred eighty-one million, five hundred twenty-eight thousand, six hundred forty".