80687999981 has 2 divisors, whose sum is σ = 80687999982. Its totient is φ = 80687999980.

The previous prime is 80687999971. The next prime is 80688000061. The reversal of 80687999981 is 18999978608.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61281002500 + 19406997481 = 247550^2 + 139309^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80687999981 is a prime.

It is a super-2 number, since 2×80687999981² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 80687999899 and 80687999908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80687999971) 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, 40343999990 + 40343999991.

It is an arithmetic number, because the mean of its divisors is an integer number (40343999991).

Almost surely, 2^80687999981 is an apocalyptic number.

It is an amenable number.

80687999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

80687999981 is an equidigital number, since it uses as much as digits as its factorization.

80687999981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 141087744, while the sum is 74.

The spelling of 80687999981 in words is "eighty billion, six hundred eighty-seven million, nine hundred ninety-nine thousand, nine hundred eighty-one".