216660066557 has 16 divisors (see below), whose sum is σ = 242180759040. Its totient is φ = 192122506800.

The previous prime is 216660066551. The next prime is 216660066563. The reversal of 216660066557 is 755660066612.

It is an interprime number because it is at equal distance from previous prime (216660066551) and next prime (216660066563).

It is a cyclic number.

It is not a de Polignac number, because 216660066557 - 2²⁴ = 216643289341 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216660066551) 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, 39632 + ... + 659462.

It is an arithmetic number, because the mean of its divisors is an integer number (15136297440).

Almost surely, 2^216660066557 is an apocalyptic number.

It is an amenable number.

216660066557 is a deficient number, since it is larger than the sum of its proper divisors (25520692483).

216660066557 is a wasteful number, since it uses less digits than its factorization.

216660066557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620624.

The product of its (nonzero) digits is 2721600, while the sum is 50.

The spelling of 216660066557 in words is "two hundred sixteen billion, six hundred sixty million, sixty-six thousand, five hundred fifty-seven".