1221401244 has 288 divisors, whose sum is σ = 3792096000. Its totient is φ = 303077376.

The previous prime is 1221401243. The next prime is 1221401257. The reversal of 1221401244 is 4421041221.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 1221401244.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221401243) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11205462 + ... + 11205570.

It is an arithmetic number, because the mean of its divisors is an integer number (13167000).

Almost surely, 2^1221401244 is an apocalyptic number.

1221401244 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221401244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1896048000).

1221401244 is an abundant number, since it is smaller than the sum of its proper divisors (2570694756).

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

1221401244 is a wasteful number, since it uses less digits than its factorization.

1221401244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 1221401244 is about 34948.5513862878. The cubic root of 1221401244 is about 1068.9386640295.

Adding to 1221401244 its reverse (4421041221), we get a palindrome (5642442465).

The spelling of 1221401244 in words is "one billion, two hundred twenty-one million, four hundred one thousand, two hundred forty-four".