21002121110197 has 2 divisors, whose sum is σ = 21002121110198. Its totient is φ = 21002121110196.

The previous prime is 21002121110099. The next prime is 21002121110207. The reversal of 21002121110197 is 79101112120012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14027826399876 + 6974294710321 = 3745374^2 + 2640889^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002121110197 - 2¹⁵ = 21002121077429 is a prime.

It is a super-2 number, since 2×21002121110197² (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 (21002121110897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501060555098 + 10501060555099.

It is an arithmetic number, because the mean of its divisors is an integer number (10501060555099).

Almost surely, 2^{21002121110197} is an apocalyptic number.

It is an amenable number.

21002121110197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002121110197 is an equidigital number, since it uses as much as digits as its factorization.

21002121110197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 28.

The spelling of 21002121110197 in words is "twenty-one trillion, two billion, one hundred twenty-one million, one hundred ten thousand, one hundred ninety-seven".