1211200221 has 32 divisors (see below), whose sum is σ = 2060264448. Its totient is φ = 614557440.

The previous prime is 1211200219. The next prime is 1211200247. The reversal of 1211200221 is 1220021121.

It is not a de Polignac number, because 1211200221 - 2¹ = 1211200219 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1211200197 and 1211200206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211200121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51036 + ... + 70901.

It is an arithmetic number, because the mean of its divisors is an integer number (64383264).

Almost surely, 2^1211200221 is an apocalyptic number.

1211200221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211200221 is a deficient number, since it is larger than the sum of its proper divisors (849064227).

1211200221 is a wasteful number, since it uses less digits than its factorization.

1211200221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122001.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1211200221 is about 34802.3019497274. The cubic root of 1211200221 is about 1065.9544504143.

Adding to 1211200221 its reverse (1220021121), we get a palindrome (2431221342).

Subtracting 1211200221 from its reverse (1220021121), we obtain a square (8820900 = 2970²).

The spelling of 1211200221 in words is "one billion, two hundred eleven million, two hundred thousand, two hundred twenty-one".