1221011200 has 54 divisors (see below), whose sum is σ = 3022209344. Its totient is φ = 488401920.

The previous prime is 1221011177. The next prime is 1221011221. The reversal of 1221011200 is 21101221.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 88992 + ... + 101791.

Almost surely, 2^1221011200 is an apocalyptic number.

1221011200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221011200 is an abundant number, since it is smaller than the sum of its proper divisors (1801198144).

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

1221011200 is an equidigital number, since it uses as much as digits as its factorization.

1221011200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190809 (or 190790 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1221011200 is about 34942.9706808108. The cubic root of 1221011200 is about 1068.8248664539.

Adding to 1221011200 its reverse (21101221), we get a palindrome (1242112421).

The spelling of 1221011200 in words is "one billion, two hundred twenty-one million, eleven thousand, two hundred".