1221103500 has 48 divisors (see below), whose sum is σ = 3555857760. Its totient is φ = 325627200.

The previous prime is 1221103487. The next prime is 1221103549. The reversal of 1221103500 is 53011221.

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 1221103500.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 405535 + ... + 408534.

It is an arithmetic number, because the mean of its divisors is an integer number (74080370).

Almost surely, 2^1221103500 is an apocalyptic number.

1221103500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221103500 is an abundant number, since it is smaller than the sum of its proper divisors (2334754260).

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

1221103500 is a wasteful number, since it uses less digits than its factorization.

1221103500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814091 (or 814079 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 1221103500 is about 34944.2913792797. The cubic root of 1221103500 is about 1068.8517976973.

Adding to 1221103500 its reverse (53011221), we get a palindrome (1274114721).

The spelling of 1221103500 in words is "one billion, two hundred twenty-one million, one hundred three thousand, five hundred".