21671681673097 has 2 divisors, whose sum is σ = 21671681673098. Its totient is φ = 21671681673096.

The previous prime is 21671681673079. The next prime is 21671681673113. The reversal of 21671681673097 is 79037618617612.

Together with previous prime (21671681673079) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12562126287481 + 9109555385616 = 3544309^2 + 3018204^2 .

It is a cyclic number.

It is not a de Polignac number, because 21671681673097 - 2¹¹ = 21671681671049 is a prime.

It is not a weakly prime, because it can be changed into another prime (21671681673007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10835840836548 + 10835840836549.

It is an arithmetic number, because the mean of its divisors is an integer number (10835840836549).

Almost surely, 2^{21671681673097} is an apocalyptic number.

It is an amenable number.

21671681673097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21671681673097 is an equidigital number, since it uses as much as digits as its factorization.

21671681673097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32006016, while the sum is 64.

The spelling of 21671681673097 in words is "twenty-one trillion, six hundred seventy-one billion, six hundred eighty-one million, six hundred seventy-three thousand, ninety-seven".