1221066205 has 32 divisors (see below), whose sum is σ = 1576039680. Its totient is φ = 906048000.

The previous prime is 1221066169. The next prime is 1221066229. The reversal of 1221066205 is 5026601221.

It is a de Polignac number, because none of the positive numbers 2^k-1221066205 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221066205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 541330 + ... + 543580.

It is an arithmetic number, because the mean of its divisors is an integer number (49251240).

Almost surely, 2^1221066205 is an apocalyptic number.

It is an amenable number.

1221066205 is a deficient number, since it is larger than the sum of its proper divisors (354973475).

1221066205 is a wasteful number, since it uses less digits than its factorization.

1221066205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2421.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1221066205 is about 34943.7577401172. The cubic root of 1221066205 is about 1068.8409159460.

Adding to 1221066205 its reverse (5026601221), we get a palindrome (6247667426).

The spelling of 1221066205 in words is "one billion, two hundred twenty-one million, sixty-six thousand, two hundred five".