66406622406640 has 80 divisors (see below), whose sum is σ = 154941638162976. Its totient is φ = 26468694604800.

The previous prime is 66406622406623. The next prime is 66406622406647. The reversal of 66406622406640 is 4660422660466.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66406622406647) 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, 192527935 + ... + 192872545.

Almost surely, 2^{66406622406640} is an apocalyptic number.

It is an amenable number.

66406622406640 is an abundant number, since it is smaller than the sum of its proper divisors (88535015756336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66406622406640 is a wasteful number, since it uses less digits than its factorization.

66406622406640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353138 (or 353132 counting only the distinct ones).

The product of its (nonzero) digits is 11943936, while the sum is 52.

The spelling of 66406622406640 in words is "sixty-six trillion, four hundred six billion, six hundred twenty-two million, four hundred six thousand, six hundred forty".