21213612324416 has 28 divisors (see below), whose sum is σ = 42096240241692. Its totient is φ = 10606685649408.

The previous prime is 21213612324391. The next prime is 21213612324433. The reversal of 21213612324416 is 61442321631212.

It can be written as a sum of positive squares in 2 ways, for example, as 20139271782400 + 1074340542016 = 4487680^2 + 1036504^2 .

It is a super-2 number, since 2×21213612324416² (a number of 27 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 21213612324416.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3933146 + ... + 7608998.

It is an arithmetic number, because the mean of its divisors is an integer number (1503437151489).

Almost surely, 2^{21213612324416} is an apocalyptic number.

It is an amenable number.

21213612324416 is a deficient number, since it is larger than the sum of its proper divisors (20882627917276).

21213612324416 is an equidigital number, since it uses as much as digits as its factorization.

21213612324416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3766038 (or 3766028 counting only the distinct ones).

The product of its digits is 82944, while the sum is 38.

Adding to 21213612324416 its reverse (61442321631212), we get a palindrome (82655933955628).

The spelling of 21213612324416 in words is "twenty-one trillion, two hundred thirteen billion, six hundred twelve million, three hundred twenty-four thousand, four hundred sixteen".