1021020109 has 2 divisors, whose sum is σ = 1021020110. Its totient is φ = 1021020108.

The previous prime is 1021020107. The next prime is 1021020149. The reversal of 1021020109 is 9010201201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 784168009 + 236852100 = 28003^2 + 15390^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021020109 - 2¹ = 1021020107 is a prime.

Together with 1021020107, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1021020092 and 1021020101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021020107) 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 as a sum of consecutive naturals, namely, 510510054 + 510510055.

It is an arithmetic number, because the mean of its divisors is an integer number (510510055).

Almost surely, 2^1021020109 is an apocalyptic number.

It is an amenable number.

1021020109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021020109 is an equidigital number, since it uses as much as digits as its factorization.

1021020109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 1021020109 is about 31953.4052801888. The cubic root of 1021020109 is about 1006.9581745114.

The spelling of 1021020109 in words is "one billion, twenty-one million, twenty thousand, one hundred nine".