2101021009 has 2 divisors, whose sum is σ = 2101021010. Its totient is φ = 2101021008.

The previous prime is 2101020923. The next prime is 2101021019. The reversal of 2101021009 is 9001201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1513443409 + 587577600 = 38903^2 + 24240^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2101021009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2101020983 and 2101021001.

It is not a weakly prime, because it can be changed into another prime (2101021019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1050510504 + 1050510505.

It is an arithmetic number, because the mean of its divisors is an integer number (1050510505).

Almost surely, 2^2101021009 is an apocalyptic number.

It is an amenable number.

2101021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101021009 is an equidigital number, since it uses as much as digits as its factorization.

2101021009 is an evil number, because the sum of its binary digits is even.

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

The square root of 2101021009 is about 45836.8957173149. The cubic root of 2101021009 is about 1280.7866683229.

The spelling of 2101021009 in words is "two billion, one hundred one million, twenty-one thousand, nine".