217200656561 has 16 divisors (see below), whose sum is σ = 263268173568. Its totient is φ = 175158244800.

The previous prime is 217200656551. The next prime is 217200656573. The reversal of 217200656561 is 165656002712.

It is not a de Polignac number, because 217200656561 - 2¹⁴ = 217200640177 is a prime.

It is a super-2 number, since 2×217200656561² (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 (217200656551) 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, 11048150 + ... + 11067791.

It is an arithmetic number, because the mean of its divisors is an integer number (16454260848).

Almost surely, 2^217200656561 is an apocalyptic number.

It is an amenable number.

217200656561 is a deficient number, since it is larger than the sum of its proper divisors (46067517007).

217200656561 is a wasteful number, since it uses less digits than its factorization.

217200656561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22116032.

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 217200656561 in words is "two hundred seventeen billion, two hundred million, six hundred fifty-six thousand, five hundred sixty-one".