80491806721 has 2 divisors, whose sum is σ = 80491806722. Its totient is φ = 80491806720.

The previous prime is 80491806713. The next prime is 80491806761. The reversal of 80491806721 is 12760819408.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62472503025 + 18019303696 = 249945^2 + 134236^2 .

It is a cyclic number.

It is not a de Polignac number, because 80491806721 - 2³ = 80491806713 is a prime.

It is not a weakly prime, because it can be changed into another prime (80491806761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40245903360 + 40245903361.

It is an arithmetic number, because the mean of its divisors is an integer number (40245903361).

Almost surely, 2^80491806721 is an apocalyptic number.

It is an amenable number.

80491806721 is a deficient number, since it is larger than the sum of its proper divisors (1).

80491806721 is an equidigital number, since it uses as much as digits as its factorization.

80491806721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 46.

The spelling of 80491806721 in words is "eighty billion, four hundred ninety-one million, eight hundred six thousand, seven hundred twenty-one".