191213681693 has 12 divisors (see below), whose sum is σ = 205217267892. Its totient is φ = 178110474240.

The previous prime is 191213681689. The next prime is 191213681717. The reversal of 191213681693 is 396186312191.

It can be written as a sum of positive squares in 6 ways, for example, as 19123129 + 191194558564 = 4373^2 + 437258^2 .

It is not a de Polignac number, because 191213681693 - 2² = 191213681689 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191213681683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3382478 + ... + 3438543.

It is an arithmetic number, because the mean of its divisors is an integer number (17101438991).

Almost surely, 2^191213681693 is an apocalyptic number.

It is an amenable number.

191213681693 is a deficient number, since it is larger than the sum of its proper divisors (14003586199).

191213681693 is an equidigital number, since it uses as much as digits as its factorization.

191213681693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6821152 (or 6821135 counting only the distinct ones).

The product of its digits is 419904, while the sum is 50.

The spelling of 191213681693 in words is "one hundred ninety-one billion, two hundred thirteen million, six hundred eighty-one thousand, six hundred ninety-three".