9821117261 has 2 divisors, whose sum is σ = 9821117262. Its totient is φ = 9821117260.

The previous prime is 9821117249. The next prime is 9821117263. The reversal of 9821117261 is 1627111289.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7397032036 + 2424085225 = 86006^2 + 49235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9821117261 is a prime.

Together with 9821117263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9821117263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4910558630 + 4910558631.

It is an arithmetic number, because the mean of its divisors is an integer number (4910558631).

Almost surely, 2^9821117261 is an apocalyptic number.

It is an amenable number.

9821117261 is a deficient number, since it is larger than the sum of its proper divisors (1).

9821117261 is an equidigital number, since it uses as much as digits as its factorization.

9821117261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 38.

The square root of 9821117261 is about 99101.5502451904. The cubic root of 9821117261 is about 2141.5109471671.

The spelling of 9821117261 in words is "nine billion, eight hundred twenty-one million, one hundred seventeen thousand, two hundred sixty-one".