21616231664647 has 2 divisors, whose sum is σ = 21616231664648. Its totient is φ = 21616231664646.

The previous prime is 21616231664579. The next prime is 21616231664669. The reversal of 21616231664647 is 74646613261612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21616231664647 - 2³¹ = 21614084180999 is a prime.

It is a super-2 number, since 2×21616231664647² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21616231664047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808115832323 + 10808115832324.

It is an arithmetic number, because the mean of its divisors is an integer number (10808115832324).

Almost surely, 2^{21616231664647} is an apocalyptic number.

21616231664647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21616231664647 is an equidigital number, since it uses as much as digits as its factorization.

21616231664647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10450944, while the sum is 55.

The spelling of 21616231664647 in words is "twenty-one trillion, six hundred sixteen billion, two hundred thirty-one million, six hundred sixty-four thousand, six hundred forty-seven".