1213866 has 40 divisors (see below), whose sum is σ = 2787840. Its totient is φ = 394632.

The previous prime is 1213841. The next prime is 1213873. The reversal of 1213866 is 6683121.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9495 + ... + 9621.

It is an arithmetic number, because the mean of its divisors is an integer number (69696).

2^1213866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1393920).

1213866 is an abundant number, since it is smaller than the sum of its proper divisors (1573974).

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

1213866 is a wasteful number, since it uses less digits than its factorization.

1213866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 191 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 1213866 is about 1101.7558713254. The cubic root of 1213866 is about 106.6735911303.

Adding to 1213866 its reverse (6683121), we get a palindrome (7896987).

It can be divided in two parts, 12138 and 66, that multiplied together give a palindrome (801108).

The spelling of 1213866 in words is "one million, two hundred thirteen thousand, eight hundred sixty-six".