21101001000197 has 2 divisors, whose sum is σ = 21101001000198. Its totient is φ = 21101001000196.

The previous prime is 21101001000193. The next prime is 21101001000229. The reversal of 21101001000197 is 79100010010112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15112609600036 + 5988391400161 = 3887494^2 + 2447119^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101001000197 - 2² = 21101001000193 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101001000193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550500500098 + 10550500500099.

It is an arithmetic number, because the mean of its divisors is an integer number (10550500500099).

Almost surely, 2^{21101001000197} is an apocalyptic number.

It is an amenable number.

21101001000197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101001000197 is an equidigital number, since it uses as much as digits as its factorization.

21101001000197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 126, while the sum is 23.

The spelling of 21101001000197 in words is "twenty-one trillion, one hundred one billion, one million, one hundred ninety-seven", and thus it is an aban number.