66131305665 has 128 divisors (see below), whose sum is σ = 115706880000. Its totient is φ = 32148679680.

The previous prime is 66131305649. The next prime is 66131305729. The reversal of 66131305665 is 56650313166.

It is not a de Polignac number, because 66131305665 - 2⁴ = 66131305649 is a prime.

It is a super-2 number, since 2×66131305665² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 245841151 + ... + 245841419.

It is an arithmetic number, because the mean of its divisors is an integer number (903960000).

Almost surely, 2^66131305665 is an apocalyptic number.

It is an amenable number.

66131305665 is a deficient number, since it is larger than the sum of its proper divisors (49575574335).

66131305665 is a wasteful number, since it uses less digits than its factorization.

66131305665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615.

The product of its (nonzero) digits is 291600, while the sum is 42.

The spelling of 66131305665 in words is "sixty-six billion, one hundred thirty-one million, three hundred five thousand, six hundred sixty-five".