1287640 has 16 divisors (see below), whose sum is σ = 2897280. Its totient is φ = 515040.

The previous prime is 1287623. The next prime is 1287661. The reversal of 1287640 is 467821.

It is a junction number, because it is equal to n+sod(n) for n = 1287599 and 1287608.

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 3 ways as a sum of consecutive naturals, for example, 16056 + ... + 16135.

It is an arithmetic number, because the mean of its divisors is an integer number (181080).

2^1287640 is an apocalyptic number.

1287640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1287640 is an abundant number, since it is smaller than the sum of its proper divisors (1609640).

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

1287640 is a wasteful number, since it uses less digits than its factorization.

1287640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32202 (or 32198 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 1287640 is about 1134.7422614850. The cubic root of 1287640 is about 108.7922986908.

The spelling of 1287640 in words is "one million, two hundred eighty-seven thousand, six hundred forty".