217798009545 has 16 divisors (see below), whose sum is σ = 350983846080. Its totient is φ = 115323261504.

The previous prime is 217798009531. The next prime is 217798009547. The reversal of 217798009545 is 545900897712.

It is not a de Polignac number, because 217798009545 - 2¹⁰ = 217798008521 is a prime.

It is a super-2 number, since 2×217798009545² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (217798009547) 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, 52227654 + ... + 52231823.

It is an arithmetic number, because the mean of its divisors is an integer number (21936490380).

Almost surely, 2^217798009545 is an apocalyptic number.

It is an amenable number.

217798009545 is a deficient number, since it is larger than the sum of its proper divisors (133185836535).

217798009545 is a wasteful number, since it uses less digits than its factorization.

217798009545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104459624.

The product of its (nonzero) digits is 6350400, while the sum is 57.

The spelling of 217798009545 in words is "two hundred seventeen billion, seven hundred ninety-eight million, nine thousand, five hundred forty-five".