1221005 has 8 divisors (see below), whose sum is σ = 1490400. Its totient is φ = 960016.

The previous prime is 1220993. The next prime is 1221019. The reversal of 1221005 is 5001221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221005 is a prime.

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, 1775 + ... + 2364.

It is an arithmetic number, because the mean of its divisors is an integer number (186300).

2^1221005 is an apocalyptic number.

It is an amenable number.

1221005 is a deficient number, since it is larger than the sum of its proper divisors (269395).

1221005 is an equidigital number, since it uses as much as digits as its factorization.

1221005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4203.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 1221005 is about 1104.9909501892. The cubic root of 1221005 is about 106.8823057373.

Adding to 1221005 its product of nonzero digits (20), we get a square (1221025 = 1105²).

Adding to 1221005 its reverse (5001221), we get a palindrome (6222226).

The spelling of 1221005 in words is "one million, two hundred twenty-one thousand, five".