21116406272 has 80 divisors (see below), whose sum is σ = 45498416040. Its totient is φ = 9732882432.

The previous prime is 21116406253. The next prime is 21116406277. The reversal of 21116406272 is 27260461112.

It can be written as a sum of positive squares in 4 ways, for example, as 12655350016 + 8461056256 = 112496^2 + 91984^2 .

It is a super-2 number, since 2×21116406272² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21116406277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6341504 + ... + 6344832.

Almost surely, 2^21116406272 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 21116406272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22749208020).

21116406272 is an abundant number, since it is smaller than the sum of its proper divisors (24382009768).

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

21116406272 is an equidigital number, since it uses as much as digits as its factorization.

21116406272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4313 (or 4297 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

Adding to 21116406272 its reverse (27260461112), we get a palindrome (48376867384).

The spelling of 21116406272 in words is "twenty-one billion, one hundred sixteen million, four hundred six thousand, two hundred seventy-two".