217051720220 has 24 divisors (see below), whose sum is σ = 456073228464. Its totient is φ = 86770285056.

The previous prime is 217051720219. The next prime is 217051720243. The reversal of 217051720220 is 22027150712.

It is a super-2 number, since 2×217051720220² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3114869 + ... + 3183788.

It is an arithmetic number, because the mean of its divisors is an integer number (19003051186).

Almost surely, 2^217051720220 is an apocalyptic number.

217051720220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217051720220 is an abundant number, since it is smaller than the sum of its proper divisors (239021508244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217051720220 is a wasteful number, since it uses less digits than its factorization.

217051720220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6300389 (or 6300387 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 29.

Adding to 217051720220 its reverse (22027150712), we get a palindrome (239078870932).

The spelling of 217051720220 in words is "two hundred seventeen billion, fifty-one million, seven hundred twenty thousand, two hundred twenty".