9771820857 has 8 divisors (see below), whose sum is σ = 14476771680. Its totient is φ = 6514547220.

The previous prime is 9771820811. The next prime is 9771820867. The reversal of 9771820857 is 7580281779.

It is a happy number.

It is not a de Polignac number, because 9771820857 - 2⁸ = 9771820601 is a prime.

It is a super-2 number, since 2×9771820857² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (9771820867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180959619 + ... + 180959672.

It is an arithmetic number, because the mean of its divisors is an integer number (1809596460).

Almost surely, 2^9771820857 is an apocalyptic number.

It is an amenable number.

9771820857 is a deficient number, since it is larger than the sum of its proper divisors (4704950823).

9771820857 is a wasteful number, since it uses less digits than its factorization.

9771820857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361919300 (or 361919294 counting only the distinct ones).

The product of its (nonzero) digits is 1975680, while the sum is 54.

The square root of 9771820857 is about 98852.5207417595. The cubic root of 9771820857 is about 2137.9218811471.

The spelling of 9771820857 in words is "nine billion, seven hundred seventy-one million, eight hundred twenty thousand, eight hundred fifty-seven".