1821783797 has 2 divisors, whose sum is σ = 1821783798. Its totient is φ = 1821783796.

The previous prime is 1821783781. The next prime is 1821783823. The reversal of 1821783797 is 7973871281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1083792241 + 737991556 = 32921^2 + 27166^2 .

It is a cyclic number.

It is not a de Polignac number, because 1821783797 - 2⁴ = 1821783781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1821783697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910891898 + 910891899.

It is an arithmetic number, because the mean of its divisors is an integer number (910891899).

Almost surely, 2^1821783797 is an apocalyptic number.

It is an amenable number.

1821783797 is a deficient number, since it is larger than the sum of its proper divisors (1).

1821783797 is an equidigital number, since it uses as much as digits as its factorization.

1821783797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1185408, while the sum is 53.

The square root of 1821783797 is about 42682.3593185756. The cubic root of 1821783797 is about 1221.3279004096.

The spelling of 1821783797 in words is "one billion, eight hundred twenty-one million, seven hundred eighty-three thousand, seven hundred ninety-seven".