2101220172 has 36 divisors (see below), whose sum is σ = 5494572720. Its totient is φ = 676254432.

The previous prime is 2101220171. The next prime is 2101220183. The reversal of 2101220172 is 2710221012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×2101220172² = 8830252422439419168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (2101220171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1005288 + ... + 1007375.

It is an arithmetic number, because the mean of its divisors is an integer number (152627020).

Almost surely, 2^2101220172 is an apocalyptic number.

It is an amenable number.

2101220172 is an abundant number, since it is smaller than the sum of its proper divisors (3393352548).

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

2101220172 is a wasteful number, since it uses less digits than its factorization.

2101220172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2012702 (or 2012697 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 2101220172 is about 45839.0681842465. The cubic root of 2101220172 is about 1280.8271371004.

Adding to 2101220172 its reverse (2710221012), we get a palindrome (4811441184).

The spelling of 2101220172 in words is "two billion, one hundred one million, two hundred twenty thousand, one hundred seventy-two".