1957197865991 has 2 divisors, whose sum is σ = 1957197865992. Its totient is φ = 1957197865990.

The previous prime is 1957197865969. The next prime is 1957197865999. The reversal of 1957197865991 is 1995687917591.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1957197865991 - 2¹⁸ = 1957197603847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1957197865999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 978598932995 + 978598932996.

It is an arithmetic number, because the mean of its divisors is an integer number (978598932996).

Almost surely, 2^{1957197865991} is an apocalyptic number.

1957197865991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1957197865991 is an equidigital number, since it uses as much as digits as its factorization.

1957197865991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 385786800, while the sum is 77.

The spelling of 1957197865991 in words is "one trillion, nine hundred fifty-seven billion, one hundred ninety-seven million, eight hundred sixty-five thousand, nine hundred ninety-one".