1221042204 has 72 divisors (see below), whose sum is σ = 3273313680. Its totient is φ = 382459392.

The previous prime is 1221042203. The next prime is 1221042241. The reversal of 1221042204 is 4022401221.

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 (1221042203) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 520867 + ... + 523205.

It is an arithmetic number, because the mean of its divisors is an integer number (45462690).

Almost surely, 2^1221042204 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 1221042204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1636656840).

1221042204 is an abundant number, since it is smaller than the sum of its proper divisors (2052271476).

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

1221042204 is a wasteful number, since it uses less digits than its factorization.

1221042204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3219 (or 3214 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 1221042204 is about 34943.4143151467. The cubic root of 1221042204 is about 1068.8339129354.

Adding to 1221042204 its reverse (4022401221), we get a palindrome (5243443425).

The spelling of 1221042204 in words is "one billion, two hundred twenty-one million, forty-two thousand, two hundred four".