66833821 has 4 divisors (see below), whose sum is σ = 67495644. Its totient is φ = 66172000.

The previous prime is 66833807. The next prime is 66833827. The reversal of 66833821 is 12833866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49702500 + 17131321 = 7050^2 + 4139^2 .

It is a cyclic number.

It is not a de Polignac number, because 66833821 - 2¹¹ = 66831773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66833827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 330760 + ... + 330961.

It is an arithmetic number, because the mean of its divisors is an integer number (16873911).

Almost surely, 2^66833821 is an apocalyptic number.

It is an amenable number.

66833821 is a deficient number, since it is larger than the sum of its proper divisors (661823).

66833821 is a wasteful number, since it uses less digits than its factorization.

66833821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661822.

The product of its digits is 41472, while the sum is 37.

The square root of 66833821 is about 8175.1954716692. The cubic root of 66833821 is about 405.8187390050.

The spelling of 66833821 in words is "sixty-six million, eight hundred thirty-three thousand, eight hundred twenty-one".