66551666515587 has 72 divisors (see below), whose sum is σ = 110672209559808. Its totient is φ = 38147175158400.

The previous prime is 66551666515561. The next prime is 66551666515613. The reversal of 66551666515587 is 78551566615566.

It is an interprime number because it is at equal distance from previous prime (66551666515561) and next prime (66551666515613).

It is not a de Polignac number, because 66551666515587 - 2¹⁰ = 66551666514563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66551666515517) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 16191162 + ... + 19881072.

It is an arithmetic number, because the mean of its divisors is an integer number (1537114021664).

Almost surely, 2^{66551666515587} is an apocalyptic number.

66551666515587 is a deficient number, since it is larger than the sum of its proper divisors (44120543044221).

66551666515587 is a wasteful number, since it uses less digits than its factorization.

66551666515587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3690129 (or 3690037 counting only the distinct ones).

The product of its digits is 1360800000, while the sum is 72.

The spelling of 66551666515587 in words is "sixty-six trillion, five hundred fifty-one billion, six hundred sixty-six million, five hundred fifteen thousand, five hundred eighty-seven".