217408649 has 4 divisors (see below), whose sum is σ = 218972880. Its totient is φ = 215844420.

The previous prime is 217408619. The next prime is 217408663. The reversal of 217408649 is 946804712.

217408649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 217408649 - 2¹² = 217404553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217408619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 781907 + ... + 782184.

It is an arithmetic number, because the mean of its divisors is an integer number (54743220).

Almost surely, 2^217408649 is an apocalyptic number.

It is an amenable number.

217408649 is a deficient number, since it is larger than the sum of its proper divisors (1564231).

217408649 is a wasteful number, since it uses less digits than its factorization.

217408649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1564230.

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 217408649 is about 14744.7837895305. The cubic root of 217408649 is about 601.3014795069.

The spelling of 217408649 in words is "two hundred seventeen million, four hundred eight thousand, six hundred forty-nine".