1781395841 has 2 divisors, whose sum is σ = 1781395842. Its totient is φ = 1781395840.

The previous prime is 1781395723. The next prime is 1781395919. The reversal of 1781395841 is 1485931871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1703955841 + 77440000 = 41279^2 + 8800^2 .

It is an emirp because it is prime and its reverse (1485931871) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1781395841 is a prime.

It is a super-2 number, since 2×1781395841² = 6346742284664194562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1781335841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890697920 + 890697921.

It is an arithmetic number, because the mean of its divisors is an integer number (890697921).

Almost surely, 2^1781395841 is an apocalyptic number.

It is an amenable number.

1781395841 is a deficient number, since it is larger than the sum of its proper divisors (1).

1781395841 is an equidigital number, since it uses as much as digits as its factorization.

1781395841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 47.

The square root of 1781395841 is about 42206.5852800247. The cubic root of 1781395841 is about 1212.2349788295.

The spelling of 1781395841 in words is "one billion, seven hundred eighty-one million, three hundred ninety-five thousand, eight hundred forty-one".