66684643 has 2 divisors, whose sum is σ = 66684644. Its totient is φ = 66684642.

The previous prime is 66684593. The next prime is 66684649. The reversal of 66684643 is 34648666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66684643 - 2²¹ = 64587491 is a prime.

It is a super-2 number, since 2×66684643² = 8893683224074898, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66684643.

It is not a weakly prime, because it can be changed into another prime (66684649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33342321 + 33342322.

It is an arithmetic number, because the mean of its divisors is an integer number (33342322).

Almost surely, 2^66684643 is an apocalyptic number.

66684643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66684643 is an equidigital number, since it uses as much as digits as its factorization.

66684643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 497664, while the sum is 43.

The square root of 66684643 is about 8166.0665561824. The cubic root of 66684643 is about 405.5165749931.

It can be divided in two parts, 6668 and 4643, that added together give a palindrome (11311).

The spelling of 66684643 in words is "sixty-six million, six hundred eighty-four thousand, six hundred forty-three".