66810943257 has 16 divisors (see below), whose sum is σ = 91305092352. Its totient is φ = 43435555200.

The previous prime is 66810943249. The next prime is 66810943259. The reversal of 66810943257 is 75234901866.

It is not a de Polignac number, because 66810943257 - 2³ = 66810943249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66810943259) 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, 816244 + ... + 894357.

It is an arithmetic number, because the mean of its divisors is an integer number (5706568272).

It is a 1-persistent number, because it is pandigital, but 2⋅66810943257 = 133621886514 is not.

Almost surely, 2^66810943257 is an apocalyptic number.

It is an amenable number.

66810943257 is a deficient number, since it is larger than the sum of its proper divisors (24494149095).

66810943257 is a wasteful number, since it uses less digits than its factorization.

66810943257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1710928.

The product of its (nonzero) digits is 2177280, while the sum is 51.

The spelling of 66810943257 in words is "sixty-six billion, eight hundred ten million, nine hundred forty-three thousand, two hundred fifty-seven".