1040805721 has 2 divisors, whose sum is σ = 1040805722. Its totient is φ = 1040805720.

The previous prime is 1040805709. The next prime is 1040805743. The reversal of 1040805721 is 1275080401.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1021761225 + 19044496 = 31965^2 + 4364^2 .

It is a cyclic number.

It is not a de Polignac number, because 1040805721 - 2⁷ = 1040805593 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1040805721.

It is not a weakly prime, because it can be changed into another prime (1040805781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 520402860 + 520402861.

It is an arithmetic number, because the mean of its divisors is an integer number (520402861).

Almost surely, 2^1040805721 is an apocalyptic number.

It is an amenable number.

1040805721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1040805721 is an equidigital number, since it uses as much as digits as its factorization.

1040805721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 1040805721 is about 32261.5207484086. The cubic root of 1040805721 is about 1013.4209785279.

The spelling of 1040805721 in words is "one billion, forty million, eight hundred five thousand, seven hundred twenty-one".