9771820997 has 2 divisors, whose sum is σ = 9771820998. Its totient is φ = 9771820996.

The previous prime is 9771820987. The next prime is 9771820999. The reversal of 9771820997 is 7990281779.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7728871396 + 2042949601 = 87914^2 + 45199^2 .

It is a cyclic number.

It is not a de Polignac number, because 9771820997 - 2⁸ = 9771820741 is a prime.

Together with 9771820999, 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 (9771820999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4885910498 + 4885910499.

It is an arithmetic number, because the mean of its divisors is an integer number (4885910499).

Almost surely, 2^9771820997 is an apocalyptic number.

It is an amenable number.

9771820997 is a deficient number, since it is larger than the sum of its proper divisors (1).

9771820997 is an equidigital number, since it uses as much as digits as its factorization.

9771820997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4000752, while the sum is 59.

The square root of 9771820997 is about 98852.5214498851. The cubic root of 9771820997 is about 2137.9218913571.

The spelling of 9771820997 in words is "nine billion, seven hundred seventy-one million, eight hundred twenty thousand, nine hundred ninety-seven".