21155144022647 has 2 divisors, whose sum is σ = 21155144022648. Its totient is φ = 21155144022646.

The previous prime is 21155144022643. The next prime is 21155144022697. The reversal of 21155144022647 is 74622044155112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21155144022647 - 2² = 21155144022643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21155144022598 and 21155144022607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21155144022643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577572011323 + 10577572011324.

It is an arithmetic number, because the mean of its divisors is an integer number (10577572011324).

Almost surely, 2^{21155144022647} is an apocalyptic number.

21155144022647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155144022647 is an equidigital number, since it uses as much as digits as its factorization.

21155144022647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 537600, while the sum is 44.

Adding to 21155144022647 its reverse (74622044155112), we get a palindrome (95777188177759).

The spelling of 21155144022647 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred forty-four million, twenty-two thousand, six hundred forty-seven".