217256313 has 16 divisors (see below), whose sum is σ = 300888000. Its totient is φ = 139272000.

The previous prime is 217256309. The next prime is 217256327. The reversal of 217256313 is 313652712.

It is not a de Polignac number, because 217256313 - 2² = 217256309 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (217256383) 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, 16863 + ... + 26811.

It is an arithmetic number, because the mean of its divisors is an integer number (18805500).

Almost surely, 2^217256313 is an apocalyptic number.

It is an amenable number.

217256313 is a deficient number, since it is larger than the sum of its proper divisors (83631687).

217256313 is a wasteful number, since it uses less digits than its factorization.

217256313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10232.

The product of its digits is 7560, while the sum is 30.

The square root of 217256313 is about 14739.6171252852. The cubic root of 217256313 is about 601.1610047753.

It can be divided in two parts, 2172 and 56313, that added together give a palindrome (58485).

The spelling of 217256313 in words is "two hundred seventeen million, two hundred fifty-six thousand, three hundred thirteen".