66633661 has 2 divisors, whose sum is σ = 66633662. Its totient is φ = 66633660.

The previous prime is 66633653. The next prime is 66633689. The reversal of 66633661 is 16633666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51926436 + 14707225 = 7206^2 + 3835^2 .

It is a cyclic number.

It is not a de Polignac number, because 66633661 - 2³ = 66633653 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66633661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66633641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33316830 + 33316831.

It is an arithmetic number, because the mean of its divisors is an integer number (33316831).

Almost surely, 2^66633661 is an apocalyptic number.

It is an amenable number.

66633661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66633661 is an equidigital number, since it uses as much as digits as its factorization.

66633661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 37.

The square root of 66633661 is about 8162.9443830030. The cubic root of 66633661 is about 405.4132062816.

The spelling of 66633661 in words is "sixty-six million, six hundred thirty-three thousand, six hundred sixty-one".