1221322005 has 24 divisors (see below), whose sum is σ = 2118006072. Its totient is φ = 651049344.

The previous prime is 1221321977. The next prime is 1221322013. The reversal of 1221322005 is 5002231221.

It can be written as a sum of positive squares in 4 ways, for example, as 171950769 + 1049371236 = 13113^2 + 32394^2 .

It is not a de Polignac number, because 1221322005 - 2¹⁴ = 1221305621 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 105987 + ... + 116943.

It is an arithmetic number, because the mean of its divisors is an integer number (88250253).

Almost surely, 2^1221322005 is an apocalyptic number.

1221322005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221322005 is a deficient number, since it is larger than the sum of its proper divisors (896684067).

1221322005 is a wasteful number, since it uses less digits than its factorization.

1221322005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13445 (or 13442 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1221322005 is about 34947.4177157626. The cubic root of 1221322005 is about 1068.9155475577.

Adding to 1221322005 its reverse (5002231221), we get a palindrome (6223553226).

The spelling of 1221322005 in words is "one billion, two hundred twenty-one million, three hundred twenty-two thousand, five".