1213666 has 4 divisors (see below), whose sum is σ = 1820502. Its totient is φ = 606832.

The previous prime is 1213661. The next prime is 1213673. The reversal of 1213666 is 6663121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 14641 = 1095^2 + 121^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1213666.

It is not an unprimeable number, because it can be changed into a prime (1213661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 303415 + ... + 303418.

2^1213666 is an apocalyptic number.

1213666 is a deficient number, since it is larger than the sum of its proper divisors (606836).

1213666 is an equidigital number, since it uses as much as digits as its factorization.

1213666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606835.

The product of its digits is 1296, while the sum is 25.

The square root of 1213666 is about 1101.6651033776. The cubic root of 1213666 is about 106.6677321942.

Adding to 1213666 its reverse (6663121), we get a palindrome (7876787).

The spelling of 1213666 in words is "one million, two hundred thirteen thousand, six hundred sixty-six".