1221718 has 16 divisors (see below), whose sum is σ = 1923264. Its totient is φ = 581440.

The previous prime is 1221707. The next prime is 1221749. The reversal of 1221718 is 8171221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3696 + ... + 4012.

It is an arithmetic number, because the mean of its divisors is an integer number (120204).

2^1221718 is an apocalyptic number.

1221718 is a deficient number, since it is larger than the sum of its proper divisors (701546).

1221718 is a wasteful number, since it uses less digits than its factorization.

1221718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407.

The product of its digits is 224, while the sum is 22.

The square root of 1221718 is about 1105.3135301805. The cubic root of 1221718 is about 106.9031061586.

Adding to 1221718 its reverse (8171221), we get a palindrome (9392939).

It can be divided in two parts, 1221 and 718, that multiplied together give a palindrome (876678).

The spelling of 1221718 in words is "one million, two hundred twenty-one thousand, seven hundred eighteen".