2157197575691 has 2 divisors, whose sum is σ = 2157197575692. Its totient is φ = 2157197575690.

The previous prime is 2157197575669. The next prime is 2157197575693. The reversal of 2157197575691 is 1965757917512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2157197575691 is a prime.

It is a Sophie Germain prime.

Together with 2157197575693, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2157197575693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078598787845 + 1078598787846.

It is an arithmetic number, because the mean of its divisors is an integer number (1078598787846).

Almost surely, 2^{2157197575691} is an apocalyptic number.

2157197575691 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157197575691 is an equidigital number, since it uses as much as digits as its factorization.

2157197575691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41674500, while the sum is 65.

The spelling of 2157197575691 in words is "two trillion, one hundred fifty-seven billion, one hundred ninety-seven million, five hundred seventy-five thousand, six hundred ninety-one".