66631505811 has 32 divisors (see below), whose sum is σ = 98057702400. Its totient is φ = 39989458944.

The previous prime is 66631505807. The next prime is 66631505881. The reversal of 66631505811 is 11850513666.

66631505811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66631505811 - 2² = 66631505807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66631505881) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 454515 + ... + 582963.

It is an arithmetic number, because the mean of its divisors is an integer number (3064303200).

Almost surely, 2^66631505811 is an apocalyptic number.

66631505811 is a deficient number, since it is larger than the sum of its proper divisors (31426196589).

66631505811 is a wasteful number, since it uses less digits than its factorization.

66631505811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128795.

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 66631505811 in words is "sixty-six billion, six hundred thirty-one million, five hundred five thousand, eight hundred eleven".