21121202176 has 48 divisors (see below), whose sum is σ = 42924674520. Its totient is φ = 10387415040.

The previous prime is 21121202171. The next prime is 21121202177. The reversal of 21121202176 is 67120212112.

It is a super-2 number, since 2×21121202176² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121202176.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121202171) 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 3 ways as a sum of consecutive naturals, for example, 40395 + ... + 209461.

Almost surely, 2^21121202176 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121202176, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21462337260).

21121202176 is an abundant number, since it is smaller than the sum of its proper divisors (21803472344).

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

21121202176 is an equidigital number, since it uses as much as digits as its factorization.

21121202176 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169150 (or 169130 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

Adding to 21121202176 its reverse (67120212112), we get a palindrome (88241414288).

The spelling of 21121202176 in words is "twenty-one billion, one hundred twenty-one million, two hundred two thousand, one hundred seventy-six".