1287640928 has 48 divisors (see below), whose sum is σ = 3067624224. Its totient is φ = 519383040.

The previous prime is 1287640927. The next prime is 1287640933. The reversal of 1287640928 is 8290467821.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287640927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 165263 + ... + 172878.

It is an arithmetic number, because the mean of its divisors is an integer number (63908838).

Almost surely, 2^1287640928 is an apocalyptic number.

It is an amenable number.

1287640928 is an abundant number, since it is smaller than the sum of its proper divisors (1779983296).

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

1287640928 is a wasteful number, since it uses less digits than its factorization.

1287640928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338175 (or 338167 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 47.

The square root of 1287640928 is about 35883.7139660877. The cubic root of 1287640928 is about 1087.9232482622.

The spelling of 1287640928 in words is "one billion, two hundred eighty-seven million, six hundred forty thousand, nine hundred twenty-eight".