66213643 has 2 divisors, whose sum is σ = 66213644. Its totient is φ = 66213642.

The previous prime is 66213629. The next prime is 66213659. The reversal of 66213643 is 34631266.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66213643 - 2⁵ = 66213611 is a prime.

It is not a weakly prime, because it can be changed into another prime (66213673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33106821 + 33106822.

It is an arithmetic number, because the mean of its divisors is an integer number (33106822).

Almost surely, 2^66213643 is an apocalyptic number.

66213643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66213643 is an equidigital number, since it uses as much as digits as its factorization.

66213643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 31.

The square root of 66213643 is about 8137.1765987964. The cubic root of 66213643 is about 404.5595842436.

The spelling of 66213643 in words is "sixty-six million, two hundred thirteen thousand, six hundred forty-three".