21012100212197 has 2 divisors, whose sum is σ = 21012100212198. Its totient is φ = 21012100212196.

The previous prime is 21012100212151. The next prime is 21012100212209. The reversal of 21012100212197 is 79121200121012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14685864141796 + 6326236070401 = 3832214^2 + 2515201^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012100212197 - 2²⁰ = 21012099163621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012100212137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506050106098 + 10506050106099.

It is an arithmetic number, because the mean of its divisors is an integer number (10506050106099).

Almost surely, 2^{21012100212197} is an apocalyptic number.

It is an amenable number.

21012100212197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012100212197 is an equidigital number, since it uses as much as digits as its factorization.

21012100212197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 29.

The spelling of 21012100212197 in words is "twenty-one trillion, twelve billion, one hundred million, two hundred twelve thousand, one hundred ninety-seven".