1781060861 has 2 divisors, whose sum is σ = 1781060862. Its totient is φ = 1781060860.

The previous prime is 1781060857. The next prime is 1781060863. The reversal of 1781060861 is 1680601871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1093624900 + 687435961 = 33070^2 + 26219^2 .

It is a cyclic number.

It is not a de Polignac number, because 1781060861 - 2² = 1781060857 is a prime.

It is a super-2 number, since 2×1781060861² = 6344355581172122642, which contains 22 as substring.

Together with 1781060863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1781060863) 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, 890530430 + 890530431.

It is an arithmetic number, because the mean of its divisors is an integer number (890530431).

Almost surely, 2^1781060861 is an apocalyptic number.

It is an amenable number.

1781060861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1781060861 is an equidigital number, since it uses as much as digits as its factorization.

1781060861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 1781060861 is about 42202.6167553625. The cubic root of 1781060861 is about 1212.1589897428.

The spelling of 1781060861 in words is "one billion, seven hundred eighty-one million, sixty thousand, eight hundred sixty-one".