1287729 has 12 divisors (see below), whose sum is σ = 1872000. Its totient is φ = 852984.

The previous prime is 1287707. The next prime is 1287731. The reversal of 1287729 is 9277821.

It is not a de Polignac number, because 1287729 - 2⁵ = 1287697 is a prime.

1287729 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1287693 and 1287702.

It is not an unprimeable number, because it can be changed into a prime (1287739) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1432 + ... + 2150.

It is an arithmetic number, because the mean of its divisors is an integer number (156000).

2^1287729 is an apocalyptic number.

It is an amenable number.

1287729 is a deficient number, since it is larger than the sum of its proper divisors (584271).

1287729 is a wasteful number, since it uses less digits than its factorization.

1287729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 924 (or 921 counting only the distinct ones).

The product of its digits is 14112, while the sum is 36.

The square root of 1287729 is about 1134.7814767611. The cubic root of 1287729 is about 108.7948051603.

It can be divided in two parts, 1287 and 729, that added together give a triangular number (2016 = T₆₃).

The spelling of 1287729 in words is "one million, two hundred eighty-seven thousand, seven hundred twenty-nine".