217672221 has 16 divisors (see below), whose sum is σ = 321004544. Its totient is φ = 130330944.

The previous prime is 217672211. The next prime is 217672223. The reversal of 217672221 is 122276712.

It is not a de Polignac number, because 217672221 - 2¹⁵ = 217639453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217672223) 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, 73981 + ... + 76866.

It is an arithmetic number, because the mean of its divisors is an integer number (20062784).

Almost surely, 2^217672221 is an apocalyptic number.

It is an amenable number.

217672221 is a deficient number, since it is larger than the sum of its proper divisors (103332323).

217672221 is a wasteful number, since it uses less digits than its factorization.

217672221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150900.

The product of its digits is 4704, while the sum is 30.

The square root of 217672221 is about 14753.7188871145. The cubic root of 217672221 is about 601.5443742143.

The spelling of 217672221 in words is "two hundred seventeen million, six hundred seventy-two thousand, two hundred twenty-one".