21113111816447 has 8 divisors (see below), whose sum is σ = 24129312214656. Its totient is φ = 18096921810072.

The previous prime is 21113111816431. The next prime is 21113111816479. The reversal of 21113111816447 is 74461811131112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21113111816447 - 2⁴ = 21113111816431 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113111812447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2395568 + ... + 6925674.

It is an arithmetic number, because the mean of its divisors is an integer number (3016164026832).

Almost surely, 2^{21113111816447} is an apocalyptic number.

21113111816447 is a deficient number, since it is larger than the sum of its proper divisors (3016200398209).

21113111816447 is an equidigital number, since it uses as much as digits as its factorization.

21113111816447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5195917.

The product of its digits is 32256, while the sum is 41.

Adding to 21113111816447 its reverse (74461811131112), we get a palindrome (95574922947559).

The spelling of 21113111816447 in words is "twenty-one trillion, one hundred thirteen billion, one hundred eleven million, eight hundred sixteen thousand, four hundred forty-seven".