66421939605 has 16 divisors (see below), whose sum is σ = 121457261184. Its totient is φ = 30364315200.

The previous prime is 66421939553. The next prime is 66421939607. The reversal of 66421939605 is 50693912466.

It is not a de Polignac number, because 66421939605 - 2¹⁰ = 66421938581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66421939607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 316294846 + ... + 316295055.

It is an arithmetic number, because the mean of its divisors is an integer number (7591078824).

Almost surely, 2^66421939605 is an apocalyptic number.

It is an amenable number.

66421939605 is a deficient number, since it is larger than the sum of its proper divisors (55035321579).

66421939605 is a wasteful number, since it uses less digits than its factorization.

66421939605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632589916.

The product of its (nonzero) digits is 2099520, while the sum is 51.

The spelling of 66421939605 in words is "sixty-six billion, four hundred twenty-one million, nine hundred thirty-nine thousand, six hundred five".