217085553521 has 16 divisors (see below), whose sum is σ = 236791234560. Its totient is φ = 198405052560.

The previous prime is 217085553511. The next prime is 217085553527. The reversal of 217085553521 is 125355580712.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217085553521 is a prime.

It is a super-2 number, since 2×217085553521² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217085553527) 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, 1870685 + ... + 1983338.

It is an arithmetic number, because the mean of its divisors is an integer number (14799452160).

Almost surely, 2^217085553521 is an apocalyptic number.

It is an amenable number.

217085553521 is a deficient number, since it is larger than the sum of its proper divisors (19705681039).

217085553521 is a wasteful number, since it uses less digits than its factorization.

217085553521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3854156.

The product of its (nonzero) digits is 420000, while the sum is 44.

The spelling of 217085553521 in words is "two hundred seventeen billion, eighty-five million, five hundred fifty-three thousand, five hundred twenty-one".