1287649 has 16 divisors (see below), whose sum is σ = 1517760. Its totient is φ = 1080000.

The previous prime is 1287623. The next prime is 1287661. The reversal of 1287649 is 9467821.

It is a cyclic number.

It is not a de Polignac number, because 1287649 - 2¹³ = 1279457 is a prime.

It is a Duffinian number.

Its product of digits (24192) is a multiple of the sum of its prime divisors (192).

It is not an unprimeable number, because it can be changed into a prime (1287749) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 12699 + ... + 12799.

It is an arithmetic number, because the mean of its divisors is an integer number (94860).

2^1287649 is an apocalyptic number.

1287649 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1287649 is a deficient number, since it is larger than the sum of its proper divisors (230111).

1287649 is a wasteful number, since it uses less digits than its factorization.

1287649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192.

The product of its digits is 24192, while the sum is 37.

The square root of 1287649 is about 1134.7462271363. The cubic root of 1287649 is about 108.7925521592.

It can be divided in two parts, 1287 and 649, that added together give a square (1936 = 44²).

The spelling of 1287649 in words is "one million, two hundred eighty-seven thousand, six hundred forty-nine".