66643533 has 24 divisors (see below), whose sum is σ = 108528000. Its totient is φ = 40388040.

The previous prime is 66643523. The next prime is 66643541. The reversal of 66643533 is 33534666.

It is a happy number.

It is not a de Polignac number, because 66643533 - 2⁸ = 66643277 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66643523) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6933 + ... + 13466.

It is an arithmetic number, because the mean of its divisors is an integer number (4522000).

Almost surely, 2^66643533 is an apocalyptic number.

It is an amenable number.

66643533 is a deficient number, since it is larger than the sum of its proper divisors (41884467).

66643533 is a wasteful number, since it uses less digits than its factorization.

66643533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20430 (or 20413 counting only the distinct ones).

The product of its digits is 116640, while the sum is 36.

The square root of 66643533 is about 8163.5490443801. The cubic root of 66643533 is about 405.4332264010.

It can be divided in two parts, 66643 and 533, that added together give a palindrome (67176).

The spelling of 66643533 in words is "sixty-six million, six hundred forty-three thousand, five hundred thirty-three".