1221618 has 16 divisors (see below), whose sum is σ = 2469600. Its totient is φ = 402816.

The previous prime is 1221601. The next prime is 1221631. The reversal of 1221618 is 8161221.

It is a junction number, because it is equal to n+sod(n) for n = 1221594 and 1221603.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 468 + ... + 1631.

It is an arithmetic number, because the mean of its divisors is an integer number (154350).

2^1221618 is an apocalyptic number.

1221618 is an abundant number, since it is smaller than the sum of its proper divisors (1247982).

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

1221618 is a wasteful number, since it uses less digits than its factorization.

1221618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2201.

The product of its digits is 192, while the sum is 21.

The square root of 1221618 is about 1105.2682932212. The cubic root of 1221618 is about 106.9001893364.

Adding to 1221618 its reverse (8161221), we get a palindrome (9382839).

The spelling of 1221618 in words is "one million, two hundred twenty-one thousand, six hundred eighteen".