21110021944447 has 2 divisors, whose sum is σ = 21110021944448. Its totient is φ = 21110021944446.

The previous prime is 21110021944441. The next prime is 21110021944457. The reversal of 21110021944447 is 74444912001112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21110021944447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110021944441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555010972223 + 10555010972224.

It is an arithmetic number, because the mean of its divisors is an integer number (10555010972224).

Almost surely, 2^{21110021944447} is an apocalyptic number.

21110021944447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110021944447 is an equidigital number, since it uses as much as digits as its factorization.

21110021944447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64512, while the sum is 40.

Adding to 21110021944447 its reverse (74444912001112), we get a palindrome (95554933945559).

The spelling of 21110021944447 in words is "twenty-one trillion, one hundred ten billion, twenty-one million, nine hundred forty-four thousand, four hundred forty-seven".