66041021 has 4 divisors (see below), whose sum is σ = 67287132. Its totient is φ = 64794912.

The previous prime is 66041009. The next prime is 66041023. The reversal of 66041021 is 12014066.

It is a happy number.

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 53860921 + 12180100 = 7339^2 + 3490^2 .

It is a cyclic number.

It is not a de Polignac number, because 66041021 - 2⁶ = 66040957 is a prime.

It is a super-2 number, since 2×66041021² = 8722832909444882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66040984 and 66041002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66041023) 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, 622976 + ... + 623081.

It is an arithmetic number, because the mean of its divisors is an integer number (16821783).

Almost surely, 2^66041021 is an apocalyptic number.

It is an amenable number.

66041021 is a deficient number, since it is larger than the sum of its proper divisors (1246111).

66041021 is a wasteful number, since it uses less digits than its factorization.

66041021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1246110.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 66041021 is about 8126.5626804941. The cubic root of 66041021 is about 404.2077098268.

Adding to 66041021 its reverse (12014066), we get a palindrome (78055087).

The spelling of 66041021 in words is "sixty-six million, forty-one thousand, twenty-one".