66151661 has 2 divisors, whose sum is σ = 66151662. Its totient is φ = 66151660.

The previous prime is 66151643. The next prime is 66151663. The reversal of 66151661 is 16615166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63282025 + 2869636 = 7955^2 + 1694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66151661 is a prime.

It is a Sophie Germain prime.

Together with 66151663, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66151663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33075830 + 33075831.

It is an arithmetic number, because the mean of its divisors is an integer number (33075831).

Almost surely, 2^66151661 is an apocalyptic number.

It is an amenable number.

66151661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66151661 is an equidigital number, since it uses as much as digits as its factorization.

66151661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 66151661 is about 8133.3671379079. The cubic root of 66151661 is about 404.4333099625.

The spelling of 66151661 in words is "sixty-six million, one hundred fifty-one thousand, six hundred sixty-one".