1966277256491 has 2 divisors, whose sum is σ = 1966277256492. Its totient is φ = 1966277256490.

The previous prime is 1966277256473. The next prime is 1966277256553. The reversal of 1966277256491 is 1946527726691.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1966277256491 - 2³⁸ = 1691399349547 is a prime.

It is not a weakly prime, because it can be changed into another prime (1966277256401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983138628245 + 983138628246.

It is an arithmetic number, because the mean of its divisors is an integer number (983138628246).

Almost surely, 2^{1966277256491} is an apocalyptic number.

1966277256491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966277256491 is an equidigital number, since it uses as much as digits as its factorization.

1966277256491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68584320, while the sum is 65.

The spelling of 1966277256491 in words is "one trillion, nine hundred sixty-six billion, two hundred seventy-seven million, two hundred fifty-six thousand, four hundred ninety-one".