1221123600 has 360 divisors, whose sum is σ = 4659389280. Its totient is φ = 306063360.

The previous prime is 1221123599. The next prime is 1221123637. The reversal of 1221123600 is 63211221.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-2 number, since 2×1221123600² = 2982285692953920000, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1652031 + ... + 1652769.

It is an arithmetic number, because the mean of its divisors is an integer number (12942748).

Almost surely, 2^1221123600 is an apocalyptic number.

1221123600 is a gapful number since it is divisible by the number (10) 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 1221123600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2329694640).

1221123600 is an abundant number, since it is smaller than the sum of its proper divisors (3438265680).

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

1221123600 is a wasteful number, since it uses less digits than its factorization.

1221123600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789 (or 766 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1221123600 is about 34944.5789787200. The cubic root of 1221123600 is about 1068.8576622843.

Adding to 1221123600 its reverse (63211221), we get a palindrome (1284334821).

The spelling of 1221123600 in words is "one billion, two hundred twenty-one million, one hundred twenty-three thousand, six hundred".