1221100201 has 4 divisors (see below), whose sum is σ = 1233190404. Its totient is φ = 1209010000.

The previous prime is 1221100193. The next prime is 1221100207. The reversal of 1221100201 is 1020011221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 847683225 + 373416976 = 29115^2 + 19324^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221100201 - 2³ = 1221100193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221100207) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 6044950 + ... + 6045151.

It is an arithmetic number, because the mean of its divisors is an integer number (308297601).

Almost surely, 2^1221100201 is an apocalyptic number.

It is an amenable number.

1221100201 is a deficient number, since it is larger than the sum of its proper divisors (12090203).

1221100201 is a wasteful number, since it uses less digits than its factorization.

1221100201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12090202.

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

The square root of 1221100201 is about 34944.2441755434. The cubic root of 1221100201 is about 1068.8508351402.

Adding to 1221100201 its reverse (1020011221), we get a palindrome (2241111422).

The spelling of 1221100201 in words is "one billion, two hundred twenty-one million, one hundred thousand, two hundred one".