1221001344 has 128 divisors (see below), whose sum is σ = 3680812800. Its totient is φ = 398287872.

The previous prime is 1221001343. The next prime is 1221001393. The reversal of 1221001344 is 4431001221.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is not an unprimeable number, because it can be changed into a prime (1221001343) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158674 + ... + 166190.

It is an arithmetic number, because the mean of its divisors is an integer number (28756350).

Almost surely, 2^1221001344 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 1221001344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1840406400).

1221001344 is an abundant number, since it is smaller than the sum of its proper divisors (2459811456).

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

1221001344 is an equidigital number, since it uses as much as digits as its factorization.

1221001344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7587 (or 7569 counting only the distinct ones).

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

The square root of 1221001344 is about 34942.8296507309. The cubic root of 1221001344 is about 1068.8219905954.

Adding to 1221001344 its reverse (4431001221), we get a palindrome (5652002565).

The spelling of 1221001344 in words is "one billion, two hundred twenty-one million, one thousand, three hundred forty-four".