21121141551647 has 2 divisors, whose sum is σ = 21121141551648. Its totient is φ = 21121141551646.

The previous prime is 21121141551547. The next prime is 21121141551649. The reversal of 21121141551647 is 74615514112112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121141551647 - 2³⁰ = 21120067809823 is a prime.

It is a super-2 number, since 2×21121141551647² (a number of 27 digits) contains 22 as substring.

Together with 21121141551649, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121141551649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560570775823 + 10560570775824.

It is an arithmetic number, because the mean of its divisors is an integer number (10560570775824).

Almost surely, 2^{21121141551647} is an apocalyptic number.

21121141551647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121141551647 is an equidigital number, since it uses as much as digits as its factorization.

21121141551647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 67200, while the sum is 41.

Adding to 21121141551647 its reverse (74615514112112), we get a palindrome (95736655663759).

The spelling of 21121141551647 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred forty-one million, five hundred fifty-one thousand, six hundred forty-seven".