1200001221 has 48 divisors (see below), whose sum is σ = 1854565440. Its totient is φ = 745562880.

The previous prime is 1200001193. The next prime is 1200001247. The reversal of 1200001221 is 1221000021.

It is not a de Polignac number, because 1200001221 - 2⁵ = 1200001189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

1200001221 is a modest number, since divided by 1221 gives 1200 as remainder.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1200001291) 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 47 ways as a sum of consecutive naturals, for example, 4240146 + ... + 4240428.

It is an arithmetic number, because the mean of its divisors is an integer number (38636780).

Almost surely, 2^1200001221 is an apocalyptic number.

It is an amenable number.

1200001221 is a deficient number, since it is larger than the sum of its proper divisors (654564219).

1200001221 is a wasteful number, since it uses less digits than its factorization.

1200001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626 (or 623 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1200001221 is about 34641.0337749900. The cubic root of 1200001221 is about 1062.6589296009.

Adding to 1200001221 its reverse (1221000021), we get a palindrome (2421001242).

It can be divided in two parts, 12000012 and 21, that multiplied together give a palindrome (252000252).

The spelling of 1200001221 in words is "one billion, two hundred million, one thousand, two hundred twenty-one".