1021200221 has 4 divisors (see below), whose sum is σ = 1021614972. Its totient is φ = 1020785472.

The previous prime is 1021200209. The next prime is 1021200241. The reversal of 1021200221 is 1220021201.

It is a happy number.

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 324504196 + 696696025 = 18014^2 + 26395^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021200221 - 2¹⁴ = 1021183837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021200241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203660 + ... + 208613.

It is an arithmetic number, because the mean of its divisors is an integer number (255403743).

Almost surely, 2^1021200221 is an apocalyptic number.

It is an amenable number.

1021200221 is a deficient number, since it is larger than the sum of its proper divisors (414751).

1021200221 is an equidigital number, since it uses as much as digits as its factorization.

1021200221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414750.

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

The square root of 1021200221 is about 31956.2235096702. The cubic root of 1021200221 is about 1007.0173815030.

Adding to 1021200221 its reverse (1220021201), we get a palindrome (2241221422).

The spelling of 1021200221 in words is "one billion, twenty-one million, two hundred thousand, two hundred twenty-one".