1288665 has 24 divisors (see below), whose sum is σ = 2553408. Its totient is φ = 588960.

The previous prime is 1288657. The next prime is 1288691. The reversal of 1288665 is 5668821.

It is a happy number.

It is not a de Polignac number, because 1288665 - 2³ = 1288657 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1731 + ... + 2360.

It is an arithmetic number, because the mean of its divisors is an integer number (106392).

2^1288665 is an apocalyptic number.

1288665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1288665 is a deficient number, since it is larger than the sum of its proper divisors (1264743).

1288665 is a wasteful number, since it uses less digits than its factorization.

1288665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4109 (or 4106 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 1288665 is about 1135.1938160508. The cubic root of 1288665 is about 108.8211583436.

Subtracting from 1288665 its product of digits (23040), we obtain a square (1265625 = 1125²).

It can be divided in two parts, 1288 and 665, that added together give a triangular number (1953 = T₆₂).

The spelling of 1288665 in words is "one million, two hundred eighty-eight thousand, six hundred sixty-five".