217728024785605 has 4 divisors (see below), whose sum is σ = 261273629742732. Its totient is φ = 174182419828480.

The previous prime is 217728024785599. The next prime is 217728024785639. The reversal of 217728024785605 is 506587420827712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27884324474721 + 189843700310884 = 5280561^2 + 13778378^2 .

It is not a de Polignac number, because 217728024785605 - 2⁹ = 217728024785093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21772802478556 + ... + 21772802478565.

It is an arithmetic number, because the mean of its divisors is an integer number (65318407435683).

Almost surely, 2^{217728024785605} is an apocalyptic number.

It is an amenable number.

217728024785605 is a deficient number, since it is larger than the sum of its proper divisors (43545604957127).

217728024785605 is an equidigital number, since it uses as much as digits as its factorization.

217728024785605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43545604957126.

The product of its (nonzero) digits is 105369600, while the sum is 64.

The spelling of 217728024785605 in words is "two hundred seventeen trillion, seven hundred twenty-eight billion, twenty-four million, seven hundred eighty-five thousand, six hundred five".