1661677358791 has 2 divisors, whose sum is σ = 1661677358792. Its totient is φ = 1661677358790.

The previous prime is 1661677358707. The next prime is 1661677358807. The reversal of 1661677358791 is 1978537761661.

It is a strong prime.

It is an emirp because it is prime and its reverse (1978537761661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661677358791 is a prime.

It is a super-2 number, since 2×1661677358791² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661677358701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830838679395 + 830838679396.

It is an arithmetic number, because the mean of its divisors is an integer number (830838679396).

Almost surely, 2^{1661677358791} is an apocalyptic number.

1661677358791 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661677358791 is an equidigital number, since it uses as much as digits as its factorization.

1661677358791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 80015040, while the sum is 67.

The spelling of 1661677358791 in words is "one trillion, six hundred sixty-one billion, six hundred seventy-seven million, three hundred fifty-eight thousand, seven hundred ninety-one".