1009689661 has 2 divisors, whose sum is σ = 1009689662. Its totient is φ = 1009689660.

The previous prime is 1009689647. The next prime is 1009689671. The reversal of 1009689661 is 1669869001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1004256100 + 5433561 = 31690^2 + 2331^2 .

It is an emirp because it is prime and its reverse (1669869001) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1996896001 and 1006986991.

It is a cyclic number.

It is not a de Polignac number, because 1009689661 - 2²⁵ = 976135229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1009689631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 504844830 + 504844831.

It is an arithmetic number, because the mean of its divisors is an integer number (504844831).

Almost surely, 2^1009689661 is an apocalyptic number.

It is an amenable number.

1009689661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1009689661 is an equidigital number, since it uses as much as digits as its factorization.

1009689661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 46.

The square root of 1009689661 is about 31775.6142505538. The cubic root of 1009689661 is about 1003.2195106276.

The spelling of 1009689661 in words is "one billion, nine million, six hundred eighty-nine thousand, six hundred sixty-one".