21667155671663 has 2 divisors, whose sum is σ = 21667155671664. Its totient is φ = 21667155671662.

The previous prime is 21667155671633. The next prime is 21667155671671. The reversal of 21667155671663 is 36617655176612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21667155671663 - 2⁶ = 21667155671599 is a prime.

It is a super-2 number, since 2×21667155671663² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21667155671596 and 21667155671605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21667155671633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10833577835831 + 10833577835832.

It is an arithmetic number, because the mean of its divisors is an integer number (10833577835832).

Almost surely, 2^{21667155671663} is an apocalyptic number.

21667155671663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21667155671663 is an equidigital number, since it uses as much as digits as its factorization.

21667155671663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57153600, while the sum is 62.

The spelling of 21667155671663 in words is "twenty-one trillion, six hundred sixty-seven billion, one hundred fifty-five million, six hundred seventy-one thousand, six hundred sixty-three".