67040021821 has 16 divisors (see below), whose sum is σ = 68912218368. Its totient is φ = 65186968000.

The previous prime is 67040021813. The next prime is 67040021827. The reversal of 67040021821 is 12812004076.

It is a cyclic number.

It is not a de Polignac number, because 67040021821 - 2³ = 67040021813 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 (67040021827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17406546 + ... + 17410396.

It is an arithmetic number, because the mean of its divisors is an integer number (4307013648).

Almost surely, 2^67040021821 is an apocalyptic number.

It is an amenable number.

67040021821 is a deficient number, since it is larger than the sum of its proper divisors (1872196547).

67040021821 is a wasteful number, since it uses less digits than its factorization.

67040021821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6212.

The product of its (nonzero) digits is 5376, while the sum is 31.

Adding to 67040021821 its reverse (12812004076), we get a palindrome (79852025897).

The spelling of 67040021821 in words is "sixty-seven billion, forty million, twenty-one thousand, eight hundred twenty-one".