1221209204 has 6 divisors (see below), whose sum is σ = 2137116114. Its totient is φ = 610604600.

The previous prime is 1221209177. The next prime is 1221209207. The reversal of 1221209204 is 4029021221.

It can be written as a sum of positive squares in only one way, i.e., 647702500 + 573506704 = 25450^2 + 23948^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1221209204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221209207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152651147 + ... + 152651154.

It is an arithmetic number, because the mean of its divisors is an integer number (356186019).

Almost surely, 2^1221209204 is an apocalyptic number.

It is an amenable number.

1221209204 is a deficient number, since it is larger than the sum of its proper divisors (915906910).

1221209204 is a wasteful number, since it uses less digits than its factorization.

1221209204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305302305 (or 305302303 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1221209204 is about 34945.8038110443. The cubic root of 1221209204 is about 1068.8826382854.

The spelling of 1221209204 in words is "one billion, two hundred twenty-one million, two hundred nine thousand, two hundred four".