1066071661 has 2 divisors, whose sum is σ = 1066071662. Its totient is φ = 1066071660.

The previous prime is 1066071659. The next prime is 1066071701. The reversal of 1066071661 is 1661706601.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 654387561 + 411684100 = 25581^2 + 20290^2 .

It is an emirp because it is prime and its reverse (1661706601) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1066071661 - 2¹ = 1066071659 is a prime.

It is a super-3 number, since 3×1066071661³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 1066071659, 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 (1066071631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 533035830 + 533035831.

It is an arithmetic number, because the mean of its divisors is an integer number (533035831).

Almost surely, 2^1066071661 is an apocalyptic number.

It is an amenable number.

1066071661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1066071661 is an equidigital number, since it uses as much as digits as its factorization.

1066071661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 1066071661 is about 32650.7528397126. The cubic root of 1066071661 is about 1021.5558918324. Note that the first 3 decimals are identical.

The spelling of 1066071661 in words is "one billion, sixty-six million, seventy-one thousand, six hundred sixty-one".