1265720198305 has 4 divisors (see below), whose sum is σ = 1518864237972. Its totient is φ = 1012576158640.

The previous prime is 1265720198263. The next prime is 1265720198339. The reversal of 1265720198305 is 5038910275621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 741057557409 + 524662640896 = 860847^2 + 724336^2 .

It is not a de Polignac number, because 1265720198305 - 2⁹ = 1265720197793 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126572019826 + ... + 126572019835.

It is an arithmetic number, because the mean of its divisors is an integer number (379716059493).

Almost surely, 2^{1265720198305} is an apocalyptic number.

It is an amenable number.

1265720198305 is a deficient number, since it is larger than the sum of its proper divisors (253144039667).

1265720198305 is an equidigital number, since it uses as much as digits as its factorization.

1265720198305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253144039666.

The product of its (nonzero) digits is 907200, while the sum is 49.

The spelling of 1265720198305 in words is "one trillion, two hundred sixty-five billion, seven hundred twenty million, one hundred ninety-eight thousand, three hundred five".