80664721 has 2 divisors, whose sum is σ = 80664722. Its totient is φ = 80664720.

The previous prime is 80664713. The next prime is 80664751. The reversal of 80664721 is 12746608.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69906321 + 10758400 = 8361^2 + 3280^2 .

It is a cyclic number.

It is not a de Polignac number, because 80664721 - 2³ = 80664713 is a prime.

It is not a weakly prime, because it can be changed into another prime (80664751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40332360 + 40332361.

It is an arithmetic number, because the mean of its divisors is an integer number (40332361).

Almost surely, 2^80664721 is an apocalyptic number.

It is an amenable number.

80664721 is a deficient number, since it is larger than the sum of its proper divisors (1).

80664721 is an equidigital number, since it uses as much as digits as its factorization.

80664721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 80664721 is about 8981.3540738577. The cubic root of 80664721 is about 432.0770627983.

The spelling of 80664721 in words is "eighty million, six hundred sixty-four thousand, seven hundred twenty-one".