1213221204 has 144 divisors (see below), whose sum is σ = 3467318400. Its totient is φ = 354892032.

The previous prime is 1213221203. The next prime is 1213221277. The reversal of 1213221204 is 4021223121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213221203) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2895307 + ... + 2895725.

It is an arithmetic number, because the mean of its divisors is an integer number (24078600).

Almost surely, 2^1213221204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213221204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1733659200).

1213221204 is an abundant number, since it is smaller than the sum of its proper divisors (2254097196).

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

1213221204 is a wasteful number, since it uses less digits than its factorization.

1213221204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 734 (or 729 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1213221204 is about 34831.3250393952. The cubic root of 1213221204 is about 1066.5469972953.

Adding to 1213221204 its reverse (4021223121), we get a palindrome (5234444325).

The spelling of 1213221204 in words is "one billion, two hundred thirteen million, two hundred twenty-one thousand, two hundred four".