66601643 has 2 divisors, whose sum is σ = 66601644. Its totient is φ = 66601642.

The previous prime is 66601567. The next prime is 66601649. The reversal of 66601643 is 34610666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66601643 - 2¹² = 66597547 is a prime.

It is not a weakly prime, because it can be changed into another prime (66601649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33300821 + 33300822.

It is an arithmetic number, because the mean of its divisors is an integer number (33300822).

Almost surely, 2^66601643 is an apocalyptic number.

66601643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66601643 is an equidigital number, since it uses as much as digits as its factorization.

66601643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 66601643 is about 8160.9829677558. The cubic root of 66601643 is about 405.3482611299.

The spelling of 66601643 in words is "sixty-six million, six hundred one thousand, six hundred forty-three".