217256497 has 4 divisors (see below), whose sum is σ = 218165760. Its totient is φ = 216347236.

The previous prime is 217256491. The next prime is 217256509. The reversal of 217256497 is 794652712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217256497 is a prime.

It is a super-2 number, since 2×217256497² = 94400770977422018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217256491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454273 + ... + 454750.

It is an arithmetic number, because the mean of its divisors is an integer number (54541440).

Almost surely, 2^217256497 is an apocalyptic number.

It is an amenable number.

217256497 is a deficient number, since it is larger than the sum of its proper divisors (909263).

217256497 is an equidigital number, since it uses as much as digits as its factorization.

217256497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909262.

The product of its digits is 211680, while the sum is 43.

The square root of 217256497 is about 14739.6233669657. The cubic root of 217256497 is about 601.1611744882.

The spelling of 217256497 in words is "two hundred seventeen million, two hundred fifty-six thousand, four hundred ninety-seven".