66821438071 has 8 divisors (see below), whose sum is σ = 67927076000. Its totient is φ = 65716129440.

The previous prime is 66821438069. The next prime is 66821438083. The reversal of 66821438071 is 17083412866.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66821438071 - 2¹ = 66821438069 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 (66821438041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 345070 + ... + 502708.

It is an arithmetic number, because the mean of its divisors is an integer number (8490884500).

Almost surely, 2^66821438071 is an apocalyptic number.

66821438071 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66821438071 is a deficient number, since it is larger than the sum of its proper divisors (1105637929).

66821438071 is a wasteful number, since it uses less digits than its factorization.

66821438071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164649.

The product of its (nonzero) digits is 387072, while the sum is 46.

The spelling of 66821438071 in words is "sixty-six billion, eight hundred twenty-one million, four hundred thirty-eight thousand, seventy-one".