221711662172 has 96 divisors (see below), whose sum is σ = 526103714304. Its totient is φ = 78946848000.

The previous prime is 221711662171. The next prime is 221711662189. The reversal of 221711662172 is 271266117122.

It is a happy number.

It is a super-2 number, since 2×221711662172² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221711662171) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 130283 + ... + 678525.

It is an arithmetic number, because the mean of its divisors is an integer number (5480247024).

Almost surely, 2^221711662172 is an apocalyptic number.

221711662172 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221711662172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263051857152).

221711662172 is an abundant number, since it is smaller than the sum of its proper divisors (304392052132).

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

221711662172 is a wasteful number, since it uses less digits than its factorization.

221711662172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548379 (or 548377 counting only the distinct ones).

The product of its digits is 28224, while the sum is 38.

Adding to 221711662172 its reverse (271266117122), we get a palindrome (492977779294).

The spelling of 221711662172 in words is "two hundred twenty-one billion, seven hundred eleven million, six hundred sixty-two thousand, one hundred seventy-two".