66839963640 has 64 divisors (see below), whose sum is σ = 201865716000. Its totient is φ = 17704361472.

The previous prime is 66839963623. The next prime is 66839963647. The reversal of 66839963640 is 4636993866.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66839963647) 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, 1851247 + ... + 1887006.

Almost surely, 2^66839963640 is an apocalyptic number.

66839963640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66839963640 is an abundant number, since it is smaller than the sum of its proper divisors (135025752360).

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

66839963640 is a wasteful number, since it uses less digits than its factorization.

66839963640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3738416 (or 3738412 counting only the distinct ones).

The product of its (nonzero) digits is 30233088, while the sum is 60.

The spelling of 66839963640 in words is "sixty-six billion, eight hundred thirty-nine million, nine hundred sixty-three thousand, six hundred forty".