21671681673029 has 2 divisors, whose sum is σ = 21671681673030. Its totient is φ = 21671681673028.

The previous prime is 21671681673007. The next prime is 21671681673041. The reversal of 21671681673029 is 92037618617612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12689660685025 + 8982020988004 = 3562255^2 + 2997002^2 .

It is a cyclic number.

It is not a de Polignac number, because 21671681673029 - 2³² = 21667386705733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21671681673079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10835840836514 + 10835840836515.

It is an arithmetic number, because the mean of its divisors is an integer number (10835840836515).

Almost surely, 2^{21671681673029} is an apocalyptic number.

It is an amenable number.

21671681673029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21671681673029 is an equidigital number, since it uses as much as digits as its factorization.

21671681673029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9144576, while the sum is 59.

The spelling of 21671681673029 in words is "twenty-one trillion, six hundred seventy-one billion, six hundred eighty-one million, six hundred seventy-three thousand, twenty-nine".