209123965693 has 2 divisors, whose sum is σ = 209123965694. Its totient is φ = 209123965692.

The previous prime is 209123965691. The next prime is 209123965819. The reversal of 209123965693 is 396569321902.

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., 176280740164 + 32843225529 = 419858^2 + 181227^2 .

It is a cyclic number.

It is not a de Polignac number, because 209123965693 - 2¹ = 209123965691 is a prime.

Together with 209123965691, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209123965691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104561982846 + 104561982847.

It is an arithmetic number, because the mean of its divisors is an integer number (104561982847).

Almost surely, 2^209123965693 is an apocalyptic number.

It is an amenable number.

209123965693 is a deficient number, since it is larger than the sum of its proper divisors (1).

209123965693 is an equidigital number, since it uses as much as digits as its factorization.

209123965693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4723920, while the sum is 55.

The spelling of 209123965693 in words is "two hundred nine billion, one hundred twenty-three million, nine hundred sixty-five thousand, six hundred ninety-three".