690916661 has 2 divisors, whose sum is σ = 690916662. Its totient is φ = 690916660.

The previous prime is 690916649. The next prime is 690916673. The reversal of 690916661 is 166619096.

690916661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (690916649) and next prime (690916673).

It can be written as a sum of positive squares in only one way, i.e., 685654225 + 5262436 = 26185^2 + 2294^2 .

It is a cyclic number.

It is not a de Polignac number, because 690916661 - 2¹⁴ = 690900277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690916631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345458330 + 345458331.

It is an arithmetic number, because the mean of its divisors is an integer number (345458331).

Almost surely, 2^690916661 is an apocalyptic number.

It is an amenable number.

690916661 is a deficient number, since it is larger than the sum of its proper divisors (1).

690916661 is an equidigital number, since it uses as much as digits as its factorization.

690916661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 44.

The square root of 690916661 is about 26285.2936259042. The cubic root of 690916661 is about 884.0467295275.

The spelling of 690916661 in words is "six hundred ninety million, nine hundred sixteen thousand, six hundred sixty-one".