66600865523 has 16 divisors (see below), whose sum is σ = 68190769920. Its totient is φ = 65030882400.

The previous prime is 66600865493. The next prime is 66600865531. The reversal of 66600865523 is 32556800666.

It is a cyclic number.

It is not a de Polignac number, because 66600865523 - 2¹⁸ = 66600603379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66600865543) 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, 3762668 + ... + 3780326.

It is an arithmetic number, because the mean of its divisors is an integer number (4261923120).

Almost surely, 2^66600865523 is an apocalyptic number.

66600865523 is a deficient number, since it is larger than the sum of its proper divisors (1589904397).

66600865523 is a wasteful number, since it uses less digits than its factorization.

66600865523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18218.

The product of its (nonzero) digits is 1555200, while the sum is 47.

The spelling of 66600865523 in words is "sixty-six billion, six hundred million, eight hundred sixty-five thousand, five hundred twenty-three".