1215666 has 12 divisors (see below), whose sum is σ = 2633982. Its totient is φ = 405216.

The previous prime is 1215649. The next prime is 1215673. The reversal of 1215666 is 6665121.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 16641 = 1095^2 + 129^2 .

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 33751 + ... + 33786.

2^1215666 is an apocalyptic number.

1215666 is an abundant number, since it is smaller than the sum of its proper divisors (1418316).

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

1215666 is a wasteful number, since it uses less digits than its factorization.

1215666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67545 (or 67542 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 1215666 is about 1102.5724465993. The cubic root of 1215666 is about 106.7262926181.

It can be divided in two parts, 1215 and 666, that added together give a palindrome (1881).

The spelling of 1215666 in words is "one million, two hundred fifteen thousand, six hundred sixty-six".