80406721 has 2 divisors, whose sum is σ = 80406722. Its totient is φ = 80406720.

The previous prime is 80406713. The next prime is 80406731. The reversal of 80406721 is 12760408.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79014321 + 1392400 = 8889^2 + 1180^2 .

It is a cyclic number.

It is not a de Polignac number, because 80406721 - 2³ = 80406713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 80406721.

It is not a weakly prime, because it can be changed into another prime (80406701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40203360 + 40203361.

It is an arithmetic number, because the mean of its divisors is an integer number (40203361).

Almost surely, 2^80406721 is an apocalyptic number.

It is an amenable number.

80406721 is a deficient number, since it is larger than the sum of its proper divisors (1).

80406721 is an equidigital number, since it uses as much as digits as its factorization.

80406721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 80406721 is about 8966.9794802932. The cubic root of 80406721 is about 431.6159155479.

The spelling of 80406721 in words is "eighty million, four hundred six thousand, seven hundred twenty-one".