80805061861981 has 2 divisors, whose sum is σ = 80805061861982. Its totient is φ = 80805061861980.

The previous prime is 80805061861913. The next prime is 80805061862033. The reversal of 80805061861981 is 18916816050808.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69877211029081 + 10927850832900 = 8359259^2 + 3305730^2 .

It is a cyclic number.

It is not a de Polignac number, because 80805061861981 - 2¹⁵ = 80805061829213 is a prime.

It is a super-2 number, since 2×80805061861981² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80805061861081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40402530930990 + 40402530930991.

It is an arithmetic number, because the mean of its divisors is an integer number (40402530930991).

Almost surely, 2^{80805061861981} is an apocalyptic number.

It is an amenable number.

80805061861981 is a deficient number, since it is larger than the sum of its proper divisors (1).

80805061861981 is an equidigital number, since it uses as much as digits as its factorization.

80805061861981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6635520, while the sum is 61.

The spelling of 80805061861981 in words is "eighty trillion, eight hundred five billion, sixty-one million, eight hundred sixty-one thousand, nine hundred eighty-one".