9210100021 has 2 divisors, whose sum is σ = 9210100022. Its totient is φ = 9210100020.

The previous prime is 9210100019. The next prime is 9210100061. The reversal of 9210100021 is 1200010129.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4611903921 + 4598196100 = 67911^2 + 67810^2 .

It is an emirp because it is prime and its reverse (1200010129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9210100021 - 2¹ = 9210100019 is a prime.

Together with 9210100019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 9210099968 and 9210100004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9210100061) 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, 4605050010 + 4605050011.

It is an arithmetic number, because the mean of its divisors is an integer number (4605050011).

Almost surely, 2^9210100021 is an apocalyptic number.

It is an amenable number.

9210100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

9210100021 is an equidigital number, since it uses as much as digits as its factorization.

9210100021 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 9210100021 is about 95969.2660230347. The cubic root of 9210100021 is about 2096.1456147894.

The spelling of 9210100021 in words is "nine billion, two hundred ten million, one hundred thousand, twenty-one".