1221221442 has 64 divisors (see below), whose sum is σ = 2884460544. Its totient is φ = 337471680.

The previous prime is 1221221437. The next prime is 1221221461. The reversal of 1221221442 is 2441221221.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 154183 + ... + 161909.

It is an arithmetic number, because the mean of its divisors is an integer number (45069696).

Almost surely, 2^1221221442 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221221442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1442230272).

1221221442 is an abundant number, since it is smaller than the sum of its proper divisors (1663239102).

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

1221221442 is a wasteful number, since it uses less digits than its factorization.

1221221442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7863.

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

The square root of 1221221442 is about 34945.9789103124. The cubic root of 1221221442 is about 1068.8862087744.

Adding to 1221221442 its reverse (2441221221), we get a palindrome (3662442663).

The spelling of 1221221442 in words is "one billion, two hundred twenty-one million, two hundred twenty-one thousand, four hundred forty-two".