66905020645 has 16 divisors (see below), whose sum is σ = 81487848960. Its totient is φ = 52727241600.

The previous prime is 66905020613. The next prime is 66905020703. The reversal of 66905020645 is 54602050966.

It is not a de Polignac number, because 66905020645 - 2⁵ = 66905020613 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156801 + ... + 397990.

It is an arithmetic number, because the mean of its divisors is an integer number (5092990560).

Almost surely, 2^66905020645 is an apocalyptic number.

It is an amenable number.

66905020645 is a deficient number, since it is larger than the sum of its proper divisors (14582828315).

66905020645 is a wasteful number, since it uses less digits than its factorization.

66905020645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555156.

The product of its (nonzero) digits is 388800, while the sum is 43.

The spelling of 66905020645 in words is "sixty-six billion, nine hundred five million, twenty thousand, six hundred forty-five".