1221210600 has 96 divisors (see below), whose sum is σ = 3824963520. Its totient is φ = 322283520.

The previous prime is 1221210593. The next prime is 1221210607. The reversal of 1221210600 is 60121221.

It is an interprime number because it is at equal distance from previous prime (1221210593) and next prime (1221210607).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1221210600.

It is not an unprimeable number, because it can be changed into a prime (1221210607) 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 23 ways as a sum of consecutive naturals, for example, 47709 + ... + 68691.

It is an arithmetic number, because the mean of its divisors is an integer number (39843370).

Almost surely, 2^1221210600 is an apocalyptic number.

1221210600 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 1221210600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1912481760).

1221210600 is an abundant number, since it is smaller than the sum of its proper divisors (2603752920).

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

1221210600 is a wasteful number, since it uses less digits than its factorization.

1221210600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21099 (or 21090 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1221210600 is about 34945.8237848244. The cubic root of 1221210600 is about 1068.8830455756.

Adding to 1221210600 its reverse (60121221), we get a palindrome (1281331821).

The spelling of 1221210600 in words is "one billion, two hundred twenty-one million, two hundred ten thousand, six hundred".