1021100221 has 4 divisors (see below), whose sum is σ = 1021186944. Its totient is φ = 1021013500.

The previous prime is 1021100209. The next prime is 1021100263. The reversal of 1021100221 is 1220011201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1021100221 is a prime.

It is a super-2 number, since 2×1021100221² = 2085291322652497682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1021100198 and 1021100207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021100281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22285 + ... + 50386.

It is an arithmetic number, because the mean of its divisors is an integer number (255296736).

Almost surely, 2^1021100221 is an apocalyptic number.

It is an amenable number.

1021100221 is a deficient number, since it is larger than the sum of its proper divisors (86723).

1021100221 is an equidigital number, since it uses as much as digits as its factorization.

1021100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86722.

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

The square root of 1021100221 is about 31954.6588309123. The cubic root of 1021100221 is about 1006.9845100434.

Adding to 1021100221 its reverse (1220011201), we get a palindrome (2241111422).

The spelling of 1021100221 in words is "one billion, twenty-one million, one hundred thousand, two hundred twenty-one".