1287693440 has 128 divisors (see below), whose sum is σ = 3393368640. Its totient is φ = 463360000.

The previous prime is 1287693431. The next prime is 1287693461. The reversal of 1287693440 is 443967821.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 1287693391 and 1287693400.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 710135 + ... + 711945.

Almost surely, 2^1287693440 is an apocalyptic number.

1287693440 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 1287693440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1696684320).

1287693440 is an abundant number, since it is smaller than the sum of its proper divisors (2105675200).

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

1287693440 is a wasteful number, since it uses less digits than its factorization.

1287693440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1942 (or 1930 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 1287693440 is about 35884.4456554647. The cubic root of 1287693440 is about 1087.9380371286.

The spelling of 1287693440 in words is "one billion, two hundred eighty-seven million, six hundred ninety-three thousand, four hundred forty".