1221020201 has 4 divisors (see below), whose sum is σ = 1244058372. Its totient is φ = 1197982032.

The previous prime is 1221020183. The next prime is 1221020231. The reversal of 1221020201 is 1020201221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1020201221 = 13 ⋅78477017.

It can be written as a sum of positive squares in 2 ways, for example, as 943964176 + 277056025 = 30724^2 + 16645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221020201 - 2⁶ = 1221020137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221020231) 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 3 ways as a sum of consecutive naturals, for example, 11519006 + ... + 11519111.

It is an arithmetic number, because the mean of its divisors is an integer number (311014593).

Almost surely, 2^1221020201 is an apocalyptic number.

It is an amenable number.

1221020201 is a deficient number, since it is larger than the sum of its proper divisors (23038171).

1221020201 is an equidigital number, since it uses as much as digits as its factorization.

1221020201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23038170.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 1221020201 is about 34943.0994761484. The cubic root of 1221020201 is about 1068.8274928204.

Adding to 1221020201 its reverse (1020201221), we get a palindrome (2241221422).

It can be divided in two parts, 1221020 and 201, that added together give a palindrome (1221221).

The spelling of 1221020201 in words is "one billion, two hundred twenty-one million, twenty thousand, two hundred one".