9815764681 has 2 divisors, whose sum is σ = 9815764682. Its totient is φ = 9815764680.

The previous prime is 9815764663. The next prime is 9815764753. The reversal of 9815764681 is 1864675189.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9121969081 + 693795600 = 95509^2 + 26340^2 .

It is a cyclic number.

It is not a de Polignac number, because 9815764681 - 2¹⁷ = 9815633609 is a prime.

It is a super-2 number, since 2×9815764681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9815764601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4907882340 + 4907882341.

It is an arithmetic number, because the mean of its divisors is an integer number (4907882341).

Almost surely, 2^9815764681 is an apocalyptic number.

It is an amenable number.

9815764681 is a deficient number, since it is larger than the sum of its proper divisors (1).

9815764681 is an equidigital number, since it uses as much as digits as its factorization.

9815764681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2903040, while the sum is 55.

The square root of 9815764681 is about 99074.5410335067. The cubic root of 9815764681 is about 2141.1218301453.

The spelling of 9815764681 in words is "nine billion, eight hundred fifteen million, seven hundred sixty-four thousand, six hundred eighty-one".