1221444400 has 60 divisors (see below), whose sum is σ = 3201306264. Its totient is φ = 444160000.

The previous prime is 1221444397. The next prime is 1221444403. The reversal of 1221444400 is 44441221.

It is an interprime number because it is at equal distance from previous prime (1221444397) and next prime (1221444403).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221444403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 134401 + ... + 143200.

Almost surely, 2^1221444400 is an apocalyptic number.

1221444400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221444400 is an abundant number, since it is smaller than the sum of its proper divisors (1979861864).

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

1221444400 is a wasteful number, since it uses less digits than its factorization.

1221444400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277630 (or 277619 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

The square root of 1221444400 is about 34949.1688027055. The cubic root of 1221444400 is about 1068.9512535516.

Adding to 1221444400 its reverse (44441221), we get a palindrome (1265885621).

It can be divided in two parts, 12 and 21444400, that added together give a palindrome (21444412).

The spelling of 1221444400 in words is "one billion, two hundred twenty-one million, four hundred forty-four thousand, four hundred".