1000566661 has 2 divisors, whose sum is σ = 1000566662. Its totient is φ = 1000566660.

The previous prime is 1000566659. The next prime is 1000566673. The reversal of 1000566661 is 1666650001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 734681025 + 265885636 = 27105^2 + 16306^2 .

It is an emirp because it is prime and its reverse (1666650001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1000566661 - 2¹ = 1000566659 is a prime.

It is a super-2 number, since 2×1000566661² = 2002267286209377842, which contains 22 as substring.

Together with 1000566659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1000566641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500283330 + 500283331.

It is an arithmetic number, because the mean of its divisors is an integer number (500283331).

Almost surely, 2^1000566661 is an apocalyptic number.

It is an amenable number.

1000566661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000566661 is an equidigital number, since it uses as much as digits as its factorization.

1000566661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 1000566661 is about 31631.7350298715. The cubic root of 1000566661 is about 1000.1888513329.

The spelling of 1000566661 in words is "one billion, five hundred sixty-six thousand, six hundred sixty-one".