693805661785409 has 2 divisors, whose sum is σ = 693805661785410. Its totient is φ = 693805661785408.

The previous prime is 693805661785403. The next prime is 693805661785487. The reversal of 693805661785409 is 904587166508396.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 667176140041009 + 26629521744400 = 25829753^2 + 5160380^2 .

It is a cyclic number.

It is not a de Polignac number, because 693805661785409 - 2²⁴ = 693805645008193 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 693805661785409.

It is not a weakly prime, because it can be changed into another prime (693805661785403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 346902830892704 + 346902830892705.

It is an arithmetic number, because the mean of its divisors is an integer number (346902830892705).

Almost surely, 2^{693805661785409} is an apocalyptic number.

It is an amenable number.

693805661785409 is a deficient number, since it is larger than the sum of its proper divisors (1).

693805661785409 is an equidigital number, since it uses as much as digits as its factorization.

693805661785409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2351462400, while the sum is 77.

The spelling of 693805661785409 in words is "six hundred ninety-three trillion, eight hundred five billion, six hundred sixty-one million, seven hundred eighty-five thousand, four hundred nine".