209691154091 has 2 divisors, whose sum is σ = 209691154092. Its totient is φ = 209691154090.

The previous prime is 209691154067. The next prime is 209691154117. The reversal of 209691154091 is 190451196902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209691154091 is a prime.

It is not a weakly prime, because it can be changed into another prime (209691154591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104845577045 + 104845577046.

It is an arithmetic number, because the mean of its divisors is an integer number (104845577046).

Almost surely, 2^209691154091 is an apocalyptic number.

209691154091 is a deficient number, since it is larger than the sum of its proper divisors (1).

209691154091 is an equidigital number, since it uses as much as digits as its factorization.

209691154091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 174960, while the sum is 47.

The spelling of 209691154091 in words is "two hundred nine billion, six hundred ninety-one million, one hundred fifty-four thousand, ninety-one".