2009781894457 has 2 divisors, whose sum is σ = 2009781894458. Its totient is φ = 2009781894456.

The previous prime is 2009781894427. The next prime is 2009781894469. The reversal of 2009781894457 is 7544981879002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1564640732736 + 445141161721 = 1250856^2 + 667189^2 .

It is a cyclic number.

It is not a de Polignac number, because 2009781894457 - 2¹¹ = 2009781892409 is a prime.

It is not a weakly prime, because it can be changed into another prime (2009781894427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1004890947228 + 1004890947229.

It is an arithmetic number, because the mean of its divisors is an integer number (1004890947229).

Almost surely, 2^{2009781894457} is an apocalyptic number.

It is an amenable number.

2009781894457 is a deficient number, since it is larger than the sum of its proper divisors (1).

2009781894457 is an equidigital number, since it uses as much as digits as its factorization.

2009781894457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40642560, while the sum is 64.

The spelling of 2009781894457 in words is "two trillion, nine billion, seven hundred eighty-one million, eight hundred ninety-four thousand, four hundred fifty-seven".