6609695821 has 2 divisors, whose sum is σ = 6609695822. Its totient is φ = 6609695820.

The previous prime is 6609695777. The next prime is 6609695843. The reversal of 6609695821 is 1285969066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6151264900 + 458430921 = 78430^2 + 21411^2 .

It is a cyclic number.

It is not a de Polignac number, because 6609695821 - 2¹⁷ = 6609564749 is a prime.

It is a super-2 number, since 2×6609695821² = 87376157692289728082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6609695861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3304847910 + 3304847911.

It is an arithmetic number, because the mean of its divisors is an integer number (3304847911).

Almost surely, 2^6609695821 is an apocalyptic number.

It is an amenable number.

6609695821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6609695821 is an equidigital number, since it uses as much as digits as its factorization.

6609695821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The square root of 6609695821 is about 81300.0357995001. The cubic root of 6609695821 is about 1876.6955515109.

The spelling of 6609695821 in words is "six billion, six hundred nine million, six hundred ninety-five thousand, eight hundred twenty-one".