1957646891 has 2 divisors, whose sum is σ = 1957646892. Its totient is φ = 1957646890.

The previous prime is 1957646879. The next prime is 1957646897. The reversal of 1957646891 is 1986467591.

It is a strong prime.

It is an emirp because it is prime and its reverse (1986467591) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1957646891 is a prime.

It is not a weakly prime, because it can be changed into another prime (1957646897) 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, 978823445 + 978823446.

It is an arithmetic number, because the mean of its divisors is an integer number (978823446).

Almost surely, 2^1957646891 is an apocalyptic number.

1957646891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1957646891 is an equidigital number, since it uses as much as digits as its factorization.

1957646891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3265920, while the sum is 56.

The square root of 1957646891 is about 44245.3036038855. The cubic root of 1957646891 is about 1250.9639265654.

The spelling of 1957646891 in words is "one billion, nine hundred fifty-seven million, six hundred forty-six thousand, eight hundred ninety-one".