211997805697 has 2 divisors, whose sum is σ = 211997805698. Its totient is φ = 211997805696.

The previous prime is 211997805689. The next prime is 211997805751. The reversal of 211997805697 is 796508799112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109412762176 + 102585043521 = 330776^2 + 320289^2 .

It is a cyclic number.

It is not a de Polignac number, because 211997805697 - 2³ = 211997805689 is a prime.

It is not a weakly prime, because it can be changed into another prime (211997806697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105998902848 + 105998902849.

It is an arithmetic number, because the mean of its divisors is an integer number (105998902849).

Almost surely, 2^211997805697 is an apocalyptic number.

It is an amenable number.

211997805697 is a deficient number, since it is larger than the sum of its proper divisors (1).

211997805697 is an equidigital number, since it uses as much as digits as its factorization.

211997805697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17146080, while the sum is 64.

The spelling of 211997805697 in words is "two hundred eleven billion, nine hundred ninety-seven million, eight hundred five thousand, six hundred ninety-seven".