66643 has 2 divisors, whose sum is σ = 66644. Its totient is φ = 66642.

The previous prime is 66629. The next prime is 66653. The reversal of 66643 is 34666.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66643 - 2¹³ = 58451 is a prime.

It is a plaindrome in base 9 and base 13.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (66653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33321 + 33322.

It is an arithmetic number, because the mean of its divisors is an integer number (33322).

2⁶⁶⁶⁴³ is an apocalyptic number.

66643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66643 is an equidigital number, since it uses as much as digits as its factorization.

66643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 25.

The square root of 66643 is about 258.1530553761. The cubic root of 66643 is about 40.5432145544.

The spelling of 66643 in words is "sixty-six thousand, six hundred forty-three".