1321666 has 4 divisors (see below), whose sum is σ = 1982502. Its totient is φ = 660832.

The previous prime is 1321657. The next prime is 1321669. The reversal of 1321666 is 6661231.

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., 1256641 + 65025 = 1121^2 + 255^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1321666.

It is not an unprimeable number, because it can be changed into a prime (1321669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330415 + ... + 330418.

2^1321666 is an apocalyptic number.

1321666 is a deficient number, since it is larger than the sum of its proper divisors (660836).

1321666 is an equidigital number, since it uses as much as digits as its factorization.

1321666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660835.

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

The square root of 1321666 is about 1149.6373341189. The cubic root of 1321666 is about 109.7422615846.

Adding to 1321666 its reverse (6661231), we get a palindrome (7982897).

It can be divided in two parts, 132 and 1666, that multiplied together give a palindrome (219912).

The spelling of 1321666 in words is "one million, three hundred twenty-one thousand, six hundred sixty-six".