2101730921 has 2 divisors, whose sum is σ = 2101730922. Its totient is φ = 2101730920.

The previous prime is 2101730887. The next prime is 2101730947. The reversal of 2101730921 is 1290371012.

It is an a-pointer prime, because the next prime (2101730947) can be obtained adding 2101730921 to its sum of digits (26).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2043040000 + 58690921 = 45200^2 + 7661^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101730921 - 2³⁰ = 1027989097 is a prime.

It is not a weakly prime, because it can be changed into another prime (2101730951) 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, 1050865460 + 1050865461.

It is an arithmetic number, because the mean of its divisors is an integer number (1050865461).

Almost surely, 2^2101730921 is an apocalyptic number.

It is an amenable number.

2101730921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2101730921 is an equidigital number, since it uses as much as digits as its factorization.

2101730921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 2101730921 is about 45844.6389559346. The cubic root of 2101730921 is about 1280.9309066769.

The spelling of 2101730921 in words is "two billion, one hundred one million, seven hundred thirty thousand, nine hundred twenty-one".