1816676766581 has 2 divisors, whose sum is σ = 1816676766582. Its totient is φ = 1816676766580.

The previous prime is 1816676766551. The next prime is 1816676766613. The reversal of 1816676766581 is 1856676766181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1806225793681 + 10450972900 = 1343959^2 + 102230^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816676766581 - 2¹⁰ = 1816676765557 is a prime.

It is a super-2 number, since 2×1816676766581² (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 (1816676766511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 908338383290 + 908338383291.

It is an arithmetic number, because the mean of its divisors is an integer number (908338383291).

Almost surely, 2^{1816676766581} is an apocalyptic number.

It is an amenable number.

1816676766581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1816676766581 is an equidigital number, since it uses as much as digits as its factorization.

1816676766581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 121927680, while the sum is 68.

The spelling of 1816676766581 in words is "one trillion, eight hundred sixteen billion, six hundred seventy-six million, seven hundred sixty-six thousand, five hundred eighty-one".