1287661540 has 96 divisors (see below), whose sum is σ = 3135283200. Its totient is φ = 439297920.

The previous prime is 1287661537. The next prime is 1287661547. The reversal of 1287661540 is 451667821.

It is a junction number, because it is equal to n+sod(n) for n = 1287661493 and 1287661502.

It is not an unprimeable number, because it can be changed into a prime (1287661547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 445821 + ... + 448699.

It is an arithmetic number, because the mean of its divisors is an integer number (32659200).

Almost surely, 2^1287661540 is an apocalyptic number.

1287661540 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 1287661540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1567641600).

1287661540 is an abundant number, since it is smaller than the sum of its proper divisors (1847621660).

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

1287661540 is a wasteful number, since it uses less digits than its factorization.

1287661540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3025 (or 3023 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 1287661540 is about 35884.0011704381. The cubic root of 1287661540 is about 1087.9290532331.

The spelling of 1287661540 in words is "one billion, two hundred eighty-seven million, six hundred sixty-one thousand, five hundred forty".