66905020644 has 192 divisors, whose sum is σ = 205280624640. Its totient is φ = 16430843520.

The previous prime is 66905020613. The next prime is 66905020703. The reversal of 66905020644 is 44602050966.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 66905020596 and 66905020605.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9599649 + ... + 9606615.

It is an arithmetic number, because the mean of its divisors is an integer number (1069169920).

Almost surely, 2^66905020644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66905020644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102640312320).

66905020644 is an abundant number, since it is smaller than the sum of its proper divisors (138375603996).

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

66905020644 is a wasteful number, since it uses less digits than its factorization.

66905020644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7558 (or 7556 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 42.

The spelling of 66905020644 in words is "sixty-six billion, nine hundred five million, twenty thousand, six hundred forty-four".