66919276821 has 4 divisors (see below), whose sum is σ = 89225702432. Its totient is φ = 44612851212.

The previous prime is 66919276813. The next prime is 66919276873. The reversal of 66919276821 is 12867291966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 66919276821 - 2³ = 66919276813 is a prime.

It is a super-2 number, since 2×66919276821² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66919276321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11153212801 + ... + 11153212806.

It is an arithmetic number, because the mean of its divisors is an integer number (22306425608).

Almost surely, 2^66919276821 is an apocalyptic number.

It is an amenable number.

66919276821 is a deficient number, since it is larger than the sum of its proper divisors (22306425611).

66919276821 is a wasteful number, since it uses less digits than its factorization.

66919276821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22306425610.

The product of its digits is 3919104, while the sum is 57.

The spelling of 66919276821 in words is "sixty-six billion, nine hundred nineteen million, two hundred seventy-six thousand, eight hundred twenty-one".