1100020021 has 2 divisors, whose sum is σ = 1100020022. Its totient is φ = 1100020020.

The previous prime is 1100019961. The next prime is 1100020039. The reversal of 1100020021 is 1200200011.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 586317796 + 513702225 = 24214^2 + 22665^2 .

It is a cyclic number.

It is not a de Polignac number, because 1100020021 - 2¹¹ = 1100017973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1100019986 and 1100020013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100020081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550010010 + 550010011.

It is an arithmetic number, because the mean of its divisors is an integer number (550010011).

Almost surely, 2^1100020021 is an apocalyptic number.

It is an amenable number.

1100020021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100020021 is an equidigital number, since it uses as much as digits as its factorization.

1100020021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 1100020021 is about 33166.5497301121. The cubic root of 1100020021 is about 1032.2863782306.

Adding to 1100020021 its reverse (1200200011), we get a palindrome (2300220032).

The spelling of 1100020021 in words is "one billion, one hundred million, twenty thousand, twenty-one".