133665661 has 2 divisors, whose sum is σ = 133665662. Its totient is φ = 133665660.

The previous prime is 133665659. The next prime is 133665677. The reversal of 133665661 is 166566331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106729561 + 26936100 = 10331^2 + 5190^2 .

It is a cyclic number.

It is not a de Polignac number, because 133665661 - 2¹ = 133665659 is a prime.

Together with 133665659, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 133665661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133660661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66832830 + 66832831.

It is an arithmetic number, because the mean of its divisors is an integer number (66832831).

Almost surely, 2^133665661 is an apocalyptic number.

It is an amenable number.

133665661 is a deficient number, since it is larger than the sum of its proper divisors (1).

133665661 is an equidigital number, since it uses as much as digits as its factorization.

133665661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 37.

The square root of 133665661 is about 11561.3866382887. The cubic root of 133665661 is about 511.2970458238.

The spelling of 133665661 in words is "one hundred thirty-three million, six hundred sixty-five thousand, six hundred sixty-one".